diff --git a/change/@fluentui-react-combobox-f06bf98c-5649-4292-b629-be7bc2e94641.json b/change/@fluentui-react-combobox-f06bf98c-5649-4292-b629-be7bc2e94641.json
new file mode 100644
index 00000000000000..ac9107a273cf54
--- /dev/null
+++ b/change/@fluentui-react-combobox-f06bf98c-5649-4292-b629-be7bc2e94641.json
@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "fix: button semantics for Combobox chevron, and pointer styles",
+  "packageName": "@fluentui/react-combobox",
+  "email": "sarah.higley@microsoft.com",
+  "dependentChangeType": "patch"
+}
diff --git a/packages/react-components/react-combobox/src/components/Combobox/Combobox.test.tsx b/packages/react-components/react-combobox/src/components/Combobox/Combobox.test.tsx
index fed215f3ee678d..14003e83921ab7 100644
--- a/packages/react-components/react-combobox/src/components/Combobox/Combobox.test.tsx
+++ b/packages/react-components/react-combobox/src/components/Combobox/Combobox.test.tsx
@@ -68,6 +68,74 @@ describe('Combobox', () => {
     expect(container.querySelector('[role=listbox]')).not.toBeNull();
   });
 
+  /* Expand icon name */
+  it('Sets the chevron button name off the aria-label prop', () => {
+    const { container } = render(
+      <Combobox aria-label="test label">
+        <Option>Red</Option>
+        <Option>Green</Option>
+        <Option>Blue</Option>
+      </Combobox>,
+    );
+
+    const chevronButton = container.querySelector('[role=button]');
+    expect(chevronButton?.getAttribute('aria-label')).toEqual('Open test label');
+  });
+
+  it('Sets the chevron button name off the aria-labelledby prop', () => {
+    const { container } = render(
+      <Combobox aria-labelledby="testId">
+        <Option>Red</Option>
+        <Option>Green</Option>
+        <Option>Blue</Option>
+      </Combobox>,
+    );
+
+    const chevronButton = container.querySelector('[role=button]');
+    const chevronId = chevronButton?.id;
+    expect(chevronButton?.getAttribute('aria-label')).toEqual('Open');
+    expect(chevronButton?.getAttribute('aria-labelledby')).toEqual(chevronId + ' testId');
+  });
+
+  it('Defaults to "Open" as the chevron label', () => {
+    const { container } = render(
+      <Combobox>
+        <Option>Red</Option>
+        <Option>Green</Option>
+        <Option>Blue</Option>
+      </Combobox>,
+    );
+
+    const chevronButton = container.querySelector('[role=button]');
+    expect(chevronButton?.getAttribute('aria-label')).toEqual('Open');
+    expect(chevronButton?.getAttribute('aria-labelledby')).toBeFalsy();
+  });
+
+  it('Respects author-provided labels for the chevron button', () => {
+    const renderedCombobox = render(
+      <Combobox aria-label="not used" aria-labelledby="not-used" expandIcon={{ 'aria-label': 'test label' }}>
+        <Option>Red</Option>
+        <Option>Green</Option>
+        <Option>Blue</Option>
+      </Combobox>,
+    );
+
+    const chevronButton = renderedCombobox.container.querySelector('[role=button]');
+    expect(chevronButton?.getAttribute('aria-label')).toEqual('test label');
+    expect(chevronButton?.getAttribute('aria-labelledby')).toBeFalsy();
+
+    renderedCombobox.rerender(
+      <Combobox aria-label="not used" aria-labelledby="not-used" expandIcon={{ 'aria-labelledby': 'testId' }}>
+        <Option>Red</Option>
+        <Option>Green</Option>
+        <Option>Blue</Option>
+      </Combobox>,
+    );
+
+    expect(chevronButton?.getAttribute('aria-label')).toBeFalsy();
+    expect(chevronButton?.getAttribute('aria-labelledby')).toEqual('testId');
+  });
+
   /* open/close tests */
   it('opens the popup on click', () => {
     const { getByRole } = render(
diff --git a/packages/react-components/react-combobox/src/components/Combobox/__snapshots__/Combobox.test.tsx.snap b/packages/react-components/react-combobox/src/components/Combobox/__snapshots__/Combobox.test.tsx.snap
index 387507376d143a..62f751823dd848 100644
--- a/packages/react-components/react-combobox/src/components/Combobox/__snapshots__/Combobox.test.tsx.snap
+++ b/packages/react-components/react-combobox/src/components/Combobox/__snapshots__/Combobox.test.tsx.snap
@@ -13,7 +13,10 @@ exports[`Combobox renders a default state 1`] = `
       value=""
     />
     <span
+      aria-expanded="false"
+      aria-label="Open"
       class="fui-Combobox__expandIcon"
+      role="button"
     >
       <svg
         aria-hidden="true"
@@ -40,7 +43,7 @@ exports[`Combobox renders an open listbox 1`] = `
     class="fui-Combobox"
   >
     <input
-      aria-activedescendant="fluent-option1"
+      aria-activedescendant="fluent-option11"
       aria-expanded="true"
       class="fui-Combobox__input"
       role="combobox"
@@ -48,7 +51,10 @@ exports[`Combobox renders an open listbox 1`] = `
       value=""
     />
     <span
+      aria-expanded="true"
+      aria-label="Open"
       class="fui-Combobox__expandIcon"
+      role="button"
     >
       <svg
         aria-hidden="true"
@@ -73,7 +79,7 @@ exports[`Combobox renders an open listbox 1`] = `
       <div
         aria-selected="false"
         class="fui-Option"
-        id="fluent-option1"
+        id="fluent-option11"
         role="option"
       >
         <span
@@ -100,7 +106,7 @@ exports[`Combobox renders an open listbox 1`] = `
       <div
         aria-selected="false"
         class="fui-Option"
-        id="fluent-option2"
+        id="fluent-option12"
         role="option"
       >
         <span
@@ -127,7 +133,7 @@ exports[`Combobox renders an open listbox 1`] = `
       <div
         aria-selected="false"
         class="fui-Option"
-        id="fluent-option3"
+        id="fluent-option13"
         role="option"
       >
         <span
diff --git a/packages/react-components/react-combobox/src/components/Combobox/useCombobox.tsx b/packages/react-components/react-combobox/src/components/Combobox/useCombobox.tsx
index 181f7dbc246f53..5f96757a5d0448 100644
--- a/packages/react-components/react-combobox/src/components/Combobox/useCombobox.tsx
+++ b/packages/react-components/react-combobox/src/components/Combobox/useCombobox.tsx
@@ -5,6 +5,7 @@ import {
   resolveShorthand,
   mergeCallbacks,
   useEventCallback,
+  useId,
   useMergedRefs,
 } from '@fluentui/react-utilities';
 import { getDropdownActionFromKey } from '../../utils/dropdownKeyActions';
@@ -44,6 +45,7 @@ export const useCombobox_unstable = (props: ComboboxProps, ref: React.Ref<HTMLIn
     value,
   } = baseState;
   const { disabled, freeform, multiselect } = props;
+  const comboId = useId('combobox-');
 
   const { primary: triggerNativeProps, root: rootNativeProps } = getPartitionedNativeProps({
     props,
@@ -200,7 +202,9 @@ export const useCombobox_unstable = (props: ComboboxProps, ref: React.Ref<HTMLIn
     expandIcon: resolveShorthand(props.expandIcon, {
       required: true,
       defaultProps: {
+        'aria-expanded': open,
         children: <ChevronDownIcon />,
+        role: 'button',
       },
     }),
     ...baseState,
@@ -233,6 +237,29 @@ export const useCombobox_unstable = (props: ComboboxProps, ref: React.Ref<HTMLIn
   if (state.expandIcon) {
     state.expandIcon.onMouseDown = onExpandIconMouseDown;
     state.expandIcon.onClick = onExpandIconClick;
+
+    // If there is no explicit aria-label, calculate default accName attribute for expandIcon button,
+    // using the following steps:
+    // 1. If there is an aria-label, it is "Open [aria-label]"
+    // 2. If there is an aria-labelledby, it is "Open [aria-labelledby target]" (using aria-labelledby + ids)
+    // 3. If there is no aria-label/ledby attr, it falls back to "Open"
+    // We can't fall back to a label/htmlFor name because of https://github.com/w3c/accname/issues/179
+    const hasExpandLabel = state.expandIcon['aria-label'] || state.expandIcon['aria-labelledby'];
+    const defaultOpenString = 'Open'; // this is english-only since it is the fallback
+    if (!hasExpandLabel) {
+      if (props['aria-labelledby']) {
+        const chevronId = state.expandIcon.id ?? `${comboId}-chevron`;
+        const chevronLabelledBy = `${chevronId} ${state.input['aria-labelledby']}`;
+
+        state.expandIcon['aria-label'] = defaultOpenString;
+        state.expandIcon.id = chevronId;
+        state.expandIcon['aria-labelledby'] = chevronLabelledBy;
+      } else if (props['aria-label']) {
+        state.expandIcon['aria-label'] = `${defaultOpenString} ${props['aria-label']}`;
+      } else {
+        state.expandIcon['aria-label'] = defaultOpenString;
+      }
+    }
   }
 
   return state;
diff --git a/packages/react-components/react-combobox/src/components/Combobox/useComboboxStyles.ts b/packages/react-components/react-combobox/src/components/Combobox/useComboboxStyles.ts
index 71fa65c0a57c6e..3626cb4650159b 100644
--- a/packages/react-components/react-combobox/src/components/Combobox/useComboboxStyles.ts
+++ b/packages/react-components/react-combobox/src/components/Combobox/useComboboxStyles.ts
@@ -197,6 +197,7 @@ const useIconStyles = makeStyles({
   icon: {
     boxSizing: 'border-box',
     color: tokens.colorNeutralStrokeAccessible,
+    cursor: 'pointer',
     display: 'block',
     fontSize: tokens.fontSizeBase500,
 
@@ -222,6 +223,7 @@ const useIconStyles = makeStyles({
   },
   disabled: {
     color: tokens.colorNeutralForegroundDisabled,
+    cursor: 'not-allowed',
   },
 });