diff --git a/profiler-cli/src/formatters.ts b/profiler-cli/src/formatters.ts
index 53838b8595..f62da72cd5 100644
--- a/profiler-cli/src/formatters.ts
+++ b/profiler-cli/src/formatters.ts
@@ -30,6 +30,7 @@ import type {
   NetworkPhaseTimings,
   MarkerGroupData,
   CallTreeNode,
+  InlineStatus,
   FilterEntry,
   SampleFilterSpec,
   ProfileLogsResult,
@@ -42,6 +43,24 @@ import { formatTimestamp as formatDuration } from 'firefox-profiler/utils/format
 // Maximum display width for function names in call-tree and sample views.
 const FUNC_NAME_WIDTH = 120;
 
+/**
+ * Suffix appended to a function name to indicate inline status.
+ * Empty string if the frame is not inlined.
+ */
+function inlineSuffix(status: InlineStatus | undefined): string {
+  if (status === 'inlined') {
+    return ' (inl)';
+  }
+  if (status === 'divergent') {
+    return ' (inl?)';
+  }
+  return '';
+}
+
+const INLINE_LEGEND =
+  'Note: (inl) = inlined by the compiler into the nearest non-inlined ancestor above. ' +
+  '(inl?) = some calls were inlined by the compiler.';
+
 /**
  * Format a SessionContext as a compact header line.
  * Shows current thread selection, zoom range, and full profile duration.
@@ -466,9 +485,10 @@ function formatCallTreeNode(
 
   // Add function handle prefix if available
   const handlePrefix = node.functionHandle ? `${node.functionHandle}. ` : '';
+  const inlineMark = inlineSuffix(node.inlineStatus);
 
   lines.push(
-    `${linePrefix}${handlePrefix}${displayName} [total: ${totalPct}%, self: ${selfPct}%]`
+    `${linePrefix}${handlePrefix}${displayName}${inlineMark} [total: ${totalPct}%, self: ${selfPct}%]`
   );
 
   // Handle children and truncation
@@ -535,6 +555,11 @@ function formatCallTree(
 ): string {
   const lines: string[] = [`${title} Call Tree:`];
 
+  if (tree.hasInlinedFrames) {
+    lines.push(INLINE_LEGEND);
+    lines.push('');
+  }
+
   // The root node is virtual, so format its children
   if (tree.children && tree.children.length > 0) {
     for (let i = 0; i < tree.children.length; i++) {
@@ -630,35 +655,21 @@ export function formatThreadSamplesResult(
   const stack = result.heaviestStack;
   output += `Heaviest stack (${stack.selfSamples.toFixed(1)} samples, ${stack.frameCount} frames):\n`;
 
+  if (stack.hasInlinedFrames) {
+    output += `  ${INLINE_LEGEND}\n\n`;
+  }
+
   if (stack.frames.length === 0) {
     output += '  (empty)\n';
   } else if (stack.frameCount <= 200) {
     // Show all frames
     for (let i = 0; i < stack.frames.length; i++) {
-      const frame = stack.frames[i];
-      const displayName = truncateFunctionName(
-        frame.nameWithLibrary,
-        FUNC_NAME_WIDTH
-      );
-      const totalCount = Math.round(frame.totalSamples);
-      const totalPct = frame.totalPercentage.toFixed(1);
-      const selfCount = Math.round(frame.selfSamples);
-      const selfPct = frame.selfPercentage.toFixed(1);
-      output += `  ${i + 1}. ${displayName} - total: ${totalCount} (${totalPct}%), self: ${selfCount} (${selfPct}%)\n`;
+      output += formatHeaviestStackFrame(stack.frames[i], i);
     }
   } else {
     // Show first 100
     for (let i = 0; i < 100; i++) {
-      const frame = stack.frames[i];
-      const displayName = truncateFunctionName(
-        frame.nameWithLibrary,
-        FUNC_NAME_WIDTH
-      );
-      const totalCount = Math.round(frame.totalSamples);
-      const totalPct = frame.totalPercentage.toFixed(1);
-      const selfCount = Math.round(frame.selfSamples);
-      const selfPct = frame.selfPercentage.toFixed(1);
-      output += `  ${i + 1}. ${displayName} - total: ${totalCount} (${totalPct}%), self: ${selfCount} (${selfPct}%)\n`;
+      output += formatHeaviestStackFrame(stack.frames[i], i);
     }
 
     // Show placeholder for skipped frames
@@ -667,22 +678,29 @@ export function formatThreadSamplesResult(
 
     // Show last 100
     for (let i = stack.frameCount - 100; i < stack.frameCount; i++) {
-      const frame = stack.frames[i];
-      const displayName = truncateFunctionName(
-        frame.nameWithLibrary,
-        FUNC_NAME_WIDTH
-      );
-      const totalCount = Math.round(frame.totalSamples);
-      const totalPct = frame.totalPercentage.toFixed(1);
-      const selfCount = Math.round(frame.selfSamples);
-      const selfPct = frame.selfPercentage.toFixed(1);
-      output += `  ${i + 1}. ${displayName} - total: ${totalCount} (${totalPct}%), self: ${selfCount} (${selfPct}%)\n`;
+      output += formatHeaviestStackFrame(stack.frames[i], i);
     }
   }
 
   return output;
 }
 
+function formatHeaviestStackFrame(
+  frame: ThreadSamplesResult['heaviestStack']['frames'][number],
+  i: number
+): string {
+  const displayName = truncateFunctionName(
+    frame.nameWithLibrary,
+    FUNC_NAME_WIDTH
+  );
+  const inlineMark = inlineSuffix(frame.inlineStatus);
+  const totalCount = Math.round(frame.totalSamples);
+  const totalPct = frame.totalPercentage.toFixed(1);
+  const selfCount = Math.round(frame.selfSamples);
+  const selfPct = frame.selfPercentage.toFixed(1);
+  return `  ${i + 1}. ${displayName}${inlineMark} - total: ${totalCount} (${totalPct}%), self: ${selfCount} (${selfPct}%)\n`;
+}
+
 /**
  * Format a ThreadSamplesTopDownResult as plain text.
  */
diff --git a/profiler-cli/src/protocol.ts b/profiler-cli/src/protocol.ts
index df510dff91..330dfe479f 100644
--- a/profiler-cli/src/protocol.ts
+++ b/profiler-cli/src/protocol.ts
@@ -29,6 +29,7 @@ export type {
   ThreadSamplesBottomUpResult,
   CallTreeNode,
   CallTreeScoringStrategy,
+  InlineStatus,
   ThreadMarkersResult,
   ThreadNetworkResult,
   NetworkRequestEntry,
diff --git a/profiler-cli/src/test/unit/call-tree-formatting.test.ts b/profiler-cli/src/test/unit/call-tree-formatting.test.ts
index 23a5dce71d..db77920db4 100644
--- a/profiler-cli/src/test/unit/call-tree-formatting.test.ts
+++ b/profiler-cli/src/test/unit/call-tree-formatting.test.ts
@@ -597,4 +597,71 @@ describe('call tree formatting', function () {
       });
     });
   });
+
+  describe('inlined frames', function () {
+    it('shows (inl) suffix and legend for inlined frames in top-down view', function () {
+      // funC is inlined into funB's native symbol (symB).
+      const result = buildTopDownResult(
+        `
+          funA[lib:XUL][address:1005][sym:symA:1000:]
+          funB[lib:XUL][address:2007][sym:symB:2000:]
+          funC[lib:XUL][address:2007][sym:symB:2000:][inl:1]
+        `,
+        { maxNodes: 10 }
+      );
+
+      const formatted = formatThreadSamplesTopDownResult(result);
+
+      expect(formatted).toContain('(inl)');
+      expect(formatted).toContain(
+        'Note: (inl) = inlined by the compiler into the nearest non-inlined ancestor above.'
+      );
+
+      // Only funC should be marked inlined.
+      const lines = formatted.split('\n');
+      const funcCLine = lines.find((l) => l.includes('funC'));
+      const funcBLine = lines.find(
+        (l) => l.includes('funB') && !l.includes('symB')
+      );
+      expect(funcCLine).toBeDefined();
+      expect(funcCLine).toContain('(inl)');
+      expect(funcBLine).toBeDefined();
+      expect(funcBLine).not.toContain('(inl)');
+    });
+
+    it('does not show legend when no frames are inlined', function () {
+      const result = buildTopDownResult(
+        `
+          A
+          B
+          C
+        `,
+        { maxNodes: 10 }
+      );
+
+      const formatted = formatThreadSamplesTopDownResult(result);
+
+      expect(formatted).not.toContain('(inl)');
+      expect(formatted).not.toContain('Note: (inl)');
+    });
+
+    it('shows (inl?) for inverted call nodes with conflicting inlining', function () {
+      // funC is inlined into two different native symbols (symB and symD) at
+      // different sites. In the inverted tree, the root funC call node merges
+      // both, resulting in divergent inlining.
+      const result = buildBottomUpResult(
+        `
+          funA[lib:XUL][address:1005][sym:symA:1000:]         funA[lib:XUL][address:1005][sym:symA:1000:]
+          funB[lib:XUL][address:2007][sym:symB:2000:]         funD[lib:XUL][address:4007][sym:symD:4000:]
+          funC[lib:XUL][address:2007][sym:symB:2000:][inl:1]  funC[lib:XUL][address:4007][sym:symD:4000:][inl:1]
+        `,
+        { maxNodes: 10 }
+      );
+
+      const formatted = formatThreadSamplesBottomUpResult(result);
+
+      expect(formatted).toContain('(inl?)');
+      expect(formatted).toContain('Note: (inl) =');
+    });
+  });
 });
diff --git a/src/profile-query/formatters/call-tree.ts b/src/profile-query/formatters/call-tree.ts
index 18353efd98..5113b81607 100644
--- a/src/profile-query/formatters/call-tree.ts
+++ b/src/profile-query/formatters/call-tree.ts
@@ -5,10 +5,33 @@
 import type { CallTree } from 'firefox-profiler/profile-logic/call-tree';
 import type { IndexIntoCallNodeTable, Lib } from 'firefox-profiler/types';
 import { assertExhaustiveCheck } from 'firefox-profiler/utils/types';
-import type { CallTreeNode, CallTreeScoringStrategy } from '../types';
+import type {
+  CallTreeNode,
+  CallTreeScoringStrategy,
+  InlineStatus,
+} from '../types';
 import { getFunctionHandle } from '../function-map';
 import { formatFunctionNameWithLibrary } from '../function-list';
 
+/**
+ * Map a call node's sourceFramesInlinedIntoSymbol value to our InlineStatus.
+ * -2 → undefined (not inlined), -1 → 'divergent', otherwise → 'inlined'.
+ */
+export function inlineStatusForNode(
+  tree: CallTree,
+  callNodeIndex: IndexIntoCallNodeTable
+): InlineStatus | undefined {
+  const inlinedInto =
+    tree._callNodeInfo.sourceFramesInlinedIntoSymbolForNode(callNodeIndex);
+  if (inlinedInto === -2) {
+    return undefined;
+  }
+  if (inlinedInto === -1) {
+    return 'divergent';
+  }
+  return 'inlined';
+}
+
 /**
  * Compute inclusion score for a call tree node.
  * The score determines priority for node budget selection.
@@ -244,6 +267,7 @@ function buildTreeStructure(
     selfSamples: 0,
     selfPercentage: 0,
     originalDepth: -1,
+    hasInlinedFrames: false,
     children: [],
   };
 
@@ -279,6 +303,11 @@ function buildTreeStructure(
         libs
       );
 
+      const inlineStatus = inlineStatusForNode(tree, callNodeIndex);
+      if (inlineStatus !== undefined) {
+        rootNode.hasInlinedFrames = true;
+      }
+
       const childNode: CallTreeNode = {
         callNodeIndex,
         functionHandle: getFunctionHandle(funcIndex),
@@ -290,6 +319,7 @@ function buildTreeStructure(
         selfSamples: childNodeData.self,
         selfPercentage: childNodeData.selfRelative * 100,
         originalDepth: childrenDepth,
+        inlineStatus,
         children: [],
       };
 
diff --git a/src/profile-query/formatters/thread-info.ts b/src/profile-query/formatters/thread-info.ts
index 4c3bc484f9..912100061a 100644
--- a/src/profile-query/formatters/thread-info.ts
+++ b/src/profile-query/formatters/thread-info.ts
@@ -26,7 +26,7 @@ import {
   extractFunctionData,
   formatFunctionNameWithLibrary,
 } from '../function-list';
-import { collectCallTree } from './call-tree';
+import { collectCallTree, inlineStatusForNode } from './call-tree';
 import type { CallTreeCollectionOptions } from './call-tree';
 import {
   computeCallTreeTimings,
@@ -157,6 +157,7 @@ export function collectThreadSamples(
   let heaviestStack: ThreadSamplesResult['heaviestStack'] = {
     selfSamples: 0,
     frameCount: 0,
+    hasInlinedFrames: false,
     frames: [],
   };
 
@@ -187,26 +188,41 @@ export function collectThreadSamples(
       if (leafNodeIndex !== null) {
         const leafNodeData = callTree.getNodeData(leafNodeIndex);
 
+        let hasInlinedFrames = false;
+        const frames = heaviestPath.map((funcIndex, depth) => {
+          const funcName = formatFunctionNameWithLibrary(
+            funcIndex,
+            thread,
+            libs
+          );
+          const funcData = funcMap.get(funcIndex);
+          const prefixPath = heaviestPath.slice(0, depth + 1);
+          const frameCallNodeIndex =
+            callNodeInfo.getCallNodeIndexFromPath(prefixPath);
+          const inlineStatus =
+            frameCallNodeIndex !== null
+              ? inlineStatusForNode(callTree, frameCallNodeIndex)
+              : undefined;
+          if (inlineStatus !== undefined) {
+            hasInlinedFrames = true;
+          }
+          return {
+            funcIndex,
+            name: funcName,
+            nameWithLibrary: funcName,
+            totalSamples: funcData?.total ?? 0,
+            totalPercentage: (funcData?.totalRelative ?? 0) * 100,
+            selfSamples: funcData?.self ?? 0,
+            selfPercentage: (funcData?.selfRelative ?? 0) * 100,
+            inlineStatus,
+          };
+        });
+
         heaviestStack = {
           selfSamples: leafNodeData.self,
           frameCount: heaviestPath.length,
-          frames: heaviestPath.map((funcIndex) => {
-            const funcName = formatFunctionNameWithLibrary(
-              funcIndex,
-              thread,
-              libs
-            );
-            const funcData = funcMap.get(funcIndex);
-            return {
-              funcIndex,
-              name: funcName,
-              nameWithLibrary: funcName,
-              totalSamples: funcData?.total ?? 0,
-              totalPercentage: (funcData?.totalRelative ?? 0) * 100,
-              selfSamples: funcData?.self ?? 0,
-              selfPercentage: (funcData?.selfRelative ?? 0) * 100,
-            };
-          }),
+          hasInlinedFrames,
+          frames,
         };
       }
     }
diff --git a/src/profile-query/types.ts b/src/profile-query/types.ts
index 5c1dcfd2f4..5cc2983a99 100644
--- a/src/profile-query/types.ts
+++ b/src/profile-query/types.ts
@@ -329,17 +329,27 @@ export type ThreadSamplesResult = {
   heaviestStack: {
     selfSamples: number;
     frameCount: number;
+    hasInlinedFrames: boolean;
     frames: Array<
       FunctionDisplayInfo & {
         totalSamples: number;
         totalPercentage: number;
         selfSamples: number;
         selfPercentage: number;
+        inlineStatus?: InlineStatus;
       }
     >;
   };
 };
 
+/**
+ * Inline status of a frame / call node.
+ * - 'inlined': all calls to this function at this call site were inlined by the
+ *   compiler into the nearest non-inlined ancestor's native function.
+ * - 'divergent': some calls were inlined, some were not.
+ */
+export type InlineStatus = 'inlined' | 'divergent';
+
 export type ThreadSamplesTopDownResult = {
   type: 'thread-samples-top-down';
   threadHandle: string;
@@ -385,6 +395,13 @@ export type CallTreeNode = FunctionDisplayInfo & {
   selfPercentage: number;
   /** Original depth in tree before collapsing single-child chains */
   originalDepth: number;
+  /** Whether this call node represents an inlined frame. Unset on the virtual root. */
+  inlineStatus?: InlineStatus;
+  /**
+   * Only set on the synthetic root. True if any node in the tree has an
+   * inlineStatus. Lets consumers skip a full tree walk to detect inlining.
+   */
+  hasInlinedFrames?: boolean;
   children: CallTreeNode[];
   /** Information about truncated children, if any were omitted */
   childrenTruncated?: {