diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinSpringServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinSpringServerCodegen.java
index 619d44868dc4..86cf4300e508 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinSpringServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinSpringServerCodegen.java
@@ -87,6 +87,7 @@ public class KotlinSpringServerCodegen extends AbstractKotlinCodegen
     public static final String SKIP_DEFAULT_API_INTERFACE = "skipDefaultApiInterface";
     public static final String SKIP_DEFAULT_DELEGATE_INTERFACE = "skipDefaultDelegateInterface";
     public static final String REACTIVE = "reactive";
+    private static final String REACTIVE_MULTIPART = "reactiveMultipart";
     public static final String INTERFACE_ONLY = "interfaceOnly";
     public static final String USE_FEIGN_CLIENT_URL = "useFeignClientUrl";
     public static final String USE_FEIGN_CLIENT = "useFeignClient";
@@ -725,6 +726,7 @@ public void processOpts() {
             writePropertyBack(SKIP_DEFAULT_INTERFACE, skipDefaultInterface);
         }
         writePropertyBack(REACTIVE, reactive);
+        writePropertyBack(REACTIVE_MULTIPART, reactive && SPRING_BOOT.equals(library));
         writePropertyBack(EXCEPTION_HANDLER, exceptionHandler);
         writePropertyBack(USE_FLOW_FOR_ARRAY_RETURN_TYPE, useFlowForArrayReturnType);
 
diff --git a/modules/openapi-generator/src/main/resources/kotlin-spring/optionalDataType.mustache b/modules/openapi-generator/src/main/resources/kotlin-spring/optionalDataType.mustache
index 1a4578db7733..2ea8b749deb4 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-spring/optionalDataType.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-spring/optionalDataType.mustache
@@ -1 +1 @@
-{{^isFile}}{{{dataType}}}{{^required}}{{^defaultValue}}?{{/defaultValue}}{{/required}}{{/isFile}}{{#isFile}}{{#isArray}}Array<{{/isArray}}org.springframework.web.multipart.MultipartFile{{#isArray}}>{{/isArray}}{{#isNullable}}?{{/isNullable}}{{/isFile}}
\ No newline at end of file
+{{^isFile}}{{{dataType}}}{{^required}}{{^defaultValue}}?{{/defaultValue}}{{/required}}{{/isFile}}{{#isFile}}{{#reactiveMultipart}}{{#isArray}}reactor.core.publisher.Flux<{{/isArray}}org.springframework.http.codec.multipart.Part{{#isArray}}>{{/isArray}}{{/reactiveMultipart}}{{^reactiveMultipart}}{{#isArray}}Array<{{/isArray}}org.springframework.web.multipart.MultipartFile{{#isArray}}>{{/isArray}}{{/reactiveMultipart}}{{#isNullable}}?{{/isNullable}}{{/isFile}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/spring/KotlinSpringServerCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/spring/KotlinSpringServerCodegenTest.java
index c99cf7a0aae1..e0e398aed1a4 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/spring/KotlinSpringServerCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/spring/KotlinSpringServerCodegenTest.java
@@ -56,6 +56,8 @@
 
 public class KotlinSpringServerCodegenTest {
 
+    private static final String MULTIPART_SPEC = "src/test/resources/3_0/form-multipart-binary-array.yaml";
+
     @Test(description = "test embedded enum array")
     public void embeddedEnumArrayTest() throws Exception {
         String baseModelPackage = "zz";
@@ -432,6 +434,26 @@ public void testNullableMultipartFile() throws IOException {
                         + "    )");
     }
 
+    @Test
+    public void testNullableMultipartFileReactive() throws IOException {
+        Map<String, File> files = generateFromContract(
+                "src/test/resources/3_0/kotlin/feat-multipartfile_nullable.yaml",
+                Map.of(KotlinSpringServerCodegen.REACTIVE, true));
+
+        assertFileContains(files.get("NullableMultipartfileApiController.kt").toPath(),
+                "file: org.springframework.http.codec.multipart.Part?"
+                        + "    )");
+        assertFileContains(files.get("NullableMultipartfileArrayApiController.kt").toPath(),
+                "files: reactor.core.publisher.Flux<org.springframework.http.codec.multipart.Part>?"
+                        + "    )");
+        assertFileContains(files.get("NonNullableMultipartfileApiController.kt").toPath(),
+                "file: org.springframework.http.codec.multipart.Part"
+                        + "    )");
+        assertFileContains(files.get("NonNullableMultipartfileArrayApiController.kt").toPath(),
+                "files: reactor.core.publisher.Flux<org.springframework.http.codec.multipart.Part>"
+                        + "    )");
+    }
+
     @Test
     public void arrayItemsCanBeNullable() throws IOException {
         File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
@@ -984,35 +1006,98 @@ public void givenOctetStreamResponseType_whenGenerateServer_thenReturnTypeIsReso
 
     @Test
     public void givenMultipartForm_whenGenerateReactiveServer_thenParameterAreCreatedAsRequestPart() throws IOException {
-        File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
-        output.deleteOnExit();
-        String outputPath = output.getAbsolutePath().replace('\\', '/');
+        Map<String, File> files = generateFromContract(
+                MULTIPART_SPEC,
+                Map.of(
+                        KotlinSpringServerCodegen.REACTIVE, true,
+                        KotlinSpringServerCodegen.SERVICE_IMPLEMENTATION, true));
 
-        final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/kotlin/petstore-with-tags.yaml");
-        final KotlinSpringServerCodegen codegen = new KotlinSpringServerCodegen();
-        codegen.setOpenAPI(openAPI);
-        codegen.setOutputDir(output.getAbsolutePath());
+        assertReactiveMultipartParameters(files, "Controller.kt");
+        assertReactiveMultipartParameters(files, "Service.kt");
+        assertReactiveMultipartParameters(files, "ServiceImpl.kt");
+        assertReactiveMultipartParameters(files, "Test.kt");
+    }
 
-        ClientOptInput input = new ClientOptInput();
-        input.openAPI(openAPI);
-        input.config(codegen);
+    @Test
+    public void givenMultipartForm_whenGenerateReactiveDelegate_thenParametersUseRequestPart() throws IOException {
+        Map<String, File> files = generateFromContract(
+                MULTIPART_SPEC,
+                Map.of(
+                        KotlinSpringServerCodegen.REACTIVE, true,
+                        KotlinSpringServerCodegen.DELEGATE_PATTERN, true));
 
-        DefaultGenerator generator = new DefaultGenerator();
+        assertReactiveMultipartParameters(files, ".kt");
+        assertReactiveMultipartParameters(files, "Delegate.kt");
+    }
 
-        generator.setGeneratorPropertyDefault(CodegenConstants.MODELS, "false");
-        generator.setGeneratorPropertyDefault(CodegenConstants.MODEL_TESTS, "false");
-        generator.setGeneratorPropertyDefault(CodegenConstants.MODEL_DOCS, "false");
-        generator.setGeneratorPropertyDefault(CodegenConstants.APIS, "true");
-        generator.setGeneratorPropertyDefault(CodegenConstants.SUPPORTING_FILES, "false");
+    @Test
+    public void givenMultipartForm_whenGenerateBlockingServer_thenMultipartFileTypesRemain() throws IOException {
+        Map<String, File> files = generateFromContract(
+                MULTIPART_SPEC,
+                Map.of(KotlinSpringServerCodegen.SERVICE_IMPLEMENTATION, true));
 
-        generator.opts(input).generate();
+        assertBlockingMultipartParameters(files, "Controller.kt");
+        assertBlockingMultipartParameters(files, "Service.kt");
+        assertBlockingMultipartParameters(files, "ServiceImpl.kt");
+        assertBlockingMultipartParameters(files, "Test.kt");
+    }
 
-        Path outputFilepath = Paths.get(outputPath + "/src/main/kotlin/org/openapitools/api/PetApiController.kt");
+    @Test
+    public void givenMultipartForm_whenGenerateReactiveDeclarativeHttpInterface_thenMultipartFileTypesRemain() throws IOException {
+        Map<String, File> files = generateFromContract(
+                MULTIPART_SPEC,
+                Map.of(
+                        KotlinSpringServerCodegen.REACTIVE, true,
+                        KotlinSpringServerCodegen.USE_FLOW_FOR_ARRAY_RETURN_TYPE, false),
+                new HashMap<>(),
+                configurator -> configurator.setLibrary(SPRING_DECLARATIVE_HTTP_INTERFACE_LIBRARY));
 
-        assertFileContains(outputFilepath,
-                "@Parameter(description = \"Additional data to pass to server\") @Valid @RequestParam(value = \"additionalMetadata\", required = false) additionalMetadata: kotlin.String?");
-        assertFileContains(outputFilepath,
-                "@Parameter(description = \"image to upload\") @Valid @RequestPart(\"image\", required = false) image: org.springframework.web.multipart.MultipartFile");
+        Path apiFile = files.get("MultipartApi.kt").toPath();
+        assertFileContains(apiFile,
+                "files: Array<org.springframework.web.multipart.MultipartFile>",
+                "file: org.springframework.web.multipart.MultipartFile",
+                "status: MultipartMixedStatus",
+                "marker: MultipartMixedRequestMarker?",
+                "statusArray: kotlin.collections.List<MultipartMixedStatus>?");
+        assertFileNotContains(apiFile, "org.springframework.http.codec.multipart.Part");
+    }
+
+    private void assertReactiveMultipartParameters(Map<String, File> files, String fileSuffix) {
+        Path arrayFile = files.get("MultipartArrayApi" + fileSuffix).toPath();
+        Path singleFile = files.get("MultipartSingleApi" + fileSuffix).toPath();
+        Path mixedFile = files.get("MultipartMixedApi" + fileSuffix).toPath();
+
+        assertFileContains(arrayFile,
+                "files: reactor.core.publisher.Flux<org.springframework.http.codec.multipart.Part>");
+        assertFileContains(singleFile,
+                "file: org.springframework.http.codec.multipart.Part");
+        assertFileContains(mixedFile,
+                "status: MultipartMixedStatus",
+                "file: org.springframework.http.codec.multipart.Part",
+                "marker: MultipartMixedRequestMarker?",
+                "statusArray: kotlin.collections.List<MultipartMixedStatus>?");
+        assertFileNotContains(arrayFile, "org.springframework.web.multipart.MultipartFile");
+        assertFileNotContains(singleFile, "org.springframework.web.multipart.MultipartFile");
+        assertFileNotContains(mixedFile, "org.springframework.web.multipart.MultipartFile");
+    }
+
+    private void assertBlockingMultipartParameters(Map<String, File> files, String fileSuffix) {
+        Path arrayFile = files.get("MultipartArrayApi" + fileSuffix).toPath();
+        Path singleFile = files.get("MultipartSingleApi" + fileSuffix).toPath();
+        Path mixedFile = files.get("MultipartMixedApi" + fileSuffix).toPath();
+
+        assertFileContains(arrayFile,
+                "files: Array<org.springframework.web.multipart.MultipartFile>");
+        assertFileContains(singleFile,
+                "file: org.springframework.web.multipart.MultipartFile");
+        assertFileContains(mixedFile,
+                "status: MultipartMixedStatus",
+                "file: org.springframework.web.multipart.MultipartFile",
+                "marker: MultipartMixedRequestMarker?",
+                "statusArray: kotlin.collections.List<MultipartMixedStatus>?");
+        assertFileNotContains(arrayFile, "org.springframework.http.codec.multipart.Part");
+        assertFileNotContains(singleFile, "org.springframework.http.codec.multipart.Part");
+        assertFileNotContains(mixedFile, "org.springframework.http.codec.multipart.Part");
 
     }
 
diff --git a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiController.kt b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiController.kt
index 165920c56390..3bb47cd5712f 100644
--- a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiController.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiController.kt
@@ -206,7 +206,7 @@ class PetApiController(@Autowired(required = true) val service: PetApiService) {
     suspend fun uploadFile(
         @Parameter(description = "ID of pet to update", required = true) @PathVariable("petId") petId: kotlin.Long,
         @Parameter(description = "Additional data to pass to server") @Valid @RequestParam(value = "additionalMetadata", required = false) additionalMetadata: kotlin.String?,
-        @Parameter(description = "file to upload") @Valid @RequestPart("file", required = false) file: org.springframework.web.multipart.MultipartFile
+        @Parameter(description = "file to upload") @Valid @RequestPart("file", required = false) file: org.springframework.http.codec.multipart.Part
     ): ResponseEntity<ModelApiResponse> {
         return ResponseEntity(service.uploadFile(petId, additionalMetadata, file), HttpStatus.valueOf(200))
     }
diff --git a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiService.kt b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiService.kt
index ed714a425820..77b25feace88 100644
--- a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiService.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiService.kt
@@ -101,5 +101,5 @@ interface PetApiService {
      * @return successful operation (status code 200)
      * @see PetApi#uploadFile
      */
-    suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.web.multipart.MultipartFile): ModelApiResponse
+    suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.http.codec.multipart.Part): ModelApiResponse
 }
diff --git a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
index 751d8c0b477e..58f2d3fcfb5a 100644
--- a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
@@ -35,7 +35,7 @@ class PetApiServiceImpl : PetApiService {
         TODO("Implement me")
     }
 
-    override suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.web.multipart.MultipartFile): ModelApiResponse {
+    override suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.http.codec.multipart.Part): ModelApiResponse {
         TODO("Implement me")
     }
 }
diff --git a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/test/kotlin/org/openapitools/api/PetApiTest.kt b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/test/kotlin/org/openapitools/api/PetApiTest.kt
index 401b2fc8829f..2bf0ad9fa15c 100644
--- a/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/test/kotlin/org/openapitools/api/PetApiTest.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive-without-flow/src/test/kotlin/org/openapitools/api/PetApiTest.kt
@@ -123,7 +123,7 @@ class PetApiTest {
     fun uploadFileTest() = runBlockingTest {
         val petId: kotlin.Long = TODO()
         val additionalMetadata: kotlin.String? = TODO()
-        val file: org.springframework.web.multipart.MultipartFile? = TODO()
+        val file: org.springframework.http.codec.multipart.Part = TODO()
         val response: ResponseEntity<ModelApiResponse> = api.uploadFile(petId, additionalMetadata, file)
 
         // TODO: test validations
diff --git a/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiController.kt b/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiController.kt
index 682a15ef48e1..b3c53ae479c6 100644
--- a/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiController.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiController.kt
@@ -206,7 +206,7 @@ class PetApiController(@Autowired(required = true) val service: PetApiService) {
     suspend fun uploadFile(
         @Parameter(description = "ID of pet to update", required = true) @PathVariable("petId") petId: kotlin.Long,
         @Parameter(description = "Additional data to pass to server") @Valid @RequestParam(value = "additionalMetadata", required = false) additionalMetadata: kotlin.String?,
-        @Parameter(description = "file to upload") @Valid @RequestPart("file", required = false) file: org.springframework.web.multipart.MultipartFile
+        @Parameter(description = "file to upload") @Valid @RequestPart("file", required = false) file: org.springframework.http.codec.multipart.Part
     ): ResponseEntity<ModelApiResponse> {
         return ResponseEntity(service.uploadFile(petId, additionalMetadata, file), HttpStatus.valueOf(200))
     }
diff --git a/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiService.kt b/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiService.kt
index 79151790a6ca..b2ac669dfb7f 100644
--- a/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiService.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiService.kt
@@ -101,5 +101,5 @@ interface PetApiService {
      * @return successful operation (status code 200)
      * @see PetApi#uploadFile
      */
-    suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.web.multipart.MultipartFile): ModelApiResponse
+    suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.http.codec.multipart.Part): ModelApiResponse
 }
diff --git a/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt b/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
index d1fce342257d..6efce8cb9beb 100644
--- a/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
@@ -35,7 +35,7 @@ class PetApiServiceImpl : PetApiService {
         TODO("Implement me")
     }
 
-    override suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.web.multipart.MultipartFile): ModelApiResponse {
+    override suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: org.springframework.http.codec.multipart.Part): ModelApiResponse {
         TODO("Implement me")
     }
 }
diff --git a/samples/server/petstore/kotlin-springboot-reactive/src/test/kotlin/org/openapitools/api/PetApiTest.kt b/samples/server/petstore/kotlin-springboot-reactive/src/test/kotlin/org/openapitools/api/PetApiTest.kt
index 26f1a1f9e0b6..50b9ced32062 100644
--- a/samples/server/petstore/kotlin-springboot-reactive/src/test/kotlin/org/openapitools/api/PetApiTest.kt
+++ b/samples/server/petstore/kotlin-springboot-reactive/src/test/kotlin/org/openapitools/api/PetApiTest.kt
@@ -123,7 +123,7 @@ class PetApiTest {
     fun uploadFileTest() = runBlockingTest {
         val petId: kotlin.Long = TODO()
         val additionalMetadata: kotlin.String? = TODO()
-        val file: org.springframework.web.multipart.MultipartFile? = TODO()
+        val file: org.springframework.http.codec.multipart.Part = TODO()
         val response: ResponseEntity<ModelApiResponse> = api.uploadFile(petId, additionalMetadata, file)
 
         // TODO: test validations