diff --git a/.changeset/short-fireants-jog.md b/.changeset/short-fireants-jog.md
new file mode 100644
index 00000000000..da0b60ece71
--- /dev/null
+++ b/.changeset/short-fireants-jog.md
@@ -0,0 +1,5 @@
+---
+"@primer/react": patch
+---
+
+Add `flex-shrink` to IconButton
diff --git a/e2e/components/IconButton.test.ts b/e2e/components/IconButton.test.ts
index 83b00e325e1..cea9f1af0ae 100644
--- a/e2e/components/IconButton.test.ts
+++ b/e2e/components/IconButton.test.ts
@@ -371,4 +371,38 @@ test.describe('IconButton', () => {
       })
     }
   })
+
+  test.describe('Flex', () => {
+    for (const theme of themes) {
+      test.describe(theme, () => {
+        test('default @vrt', async ({page}) => {
+          await visit(page, {
+            id: 'components-iconbutton-devonly--icon-button-within-flex-container',
+            globals: {
+              colorScheme: theme,
+            },
+          })
+
+          // Default state
+          expect(await page.screenshot()).toMatchSnapshot(`IconButton.Flex.${theme}.png`)
+        })
+
+        test('axe @aat', async ({page}) => {
+          await visit(page, {
+            id: 'components-iconbutton-devonly--icon-button-within-flex-container',
+            globals: {
+              colorScheme: theme,
+            },
+          })
+          await expect(page).toHaveNoViolations({
+            rules: {
+              'color-contrast': {
+                enabled: theme !== 'dark_dimmed',
+              },
+            },
+          })
+        })
+      })
+    }
+  })
 })
diff --git a/packages/react/src/Button/ButtonBase.module.css b/packages/react/src/Button/ButtonBase.module.css
index 3df7e8c1e48..00c49d97207 100644
--- a/packages/react/src/Button/ButtonBase.module.css
+++ b/packages/react/src/Button/ButtonBase.module.css
@@ -75,6 +75,7 @@
     /* stylelint-disable-next-line primer/spacing */
     padding: unset;
     place-content: center;
+    flex-shrink: 0;
 
     &:where([data-size='small']) {
       width: var(--control-small-size);
diff --git a/packages/react/src/Button/IconButton.dev.stories.tsx b/packages/react/src/Button/IconButton.dev.stories.tsx
index bc772a04f28..0850080490e 100644
--- a/packages/react/src/Button/IconButton.dev.stories.tsx
+++ b/packages/react/src/Button/IconButton.dev.stories.tsx
@@ -2,6 +2,7 @@ import {BoldIcon, ChevronDownIcon} from '@primer/octicons-react'
 import React from 'react'
 import {IconButton} from '.'
 import Box from '../Box'
+import {Stack} from '../Stack'
 
 export default {
   title: 'Components/IconButton/DevOnly',
@@ -38,3 +39,16 @@ export const CustomSizeWithStyleProp = () => (
     />
   </Box>
 )
+
+export const IconButtonWithinFlexContainer = () => (
+  <Stack direction="horizontal">
+    <span>
+      Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore
+      magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo
+      consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
+      Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+    </span>
+
+    <IconButton icon={BoldIcon} aria-label="Icon button" />
+  </Stack>
+)
diff --git a/packages/react/src/TreeView/TreeView.module.css b/packages/react/src/TreeView/TreeView.module.css
index 70be89a0310..40ded1ddc36 100644
--- a/packages/react/src/TreeView/TreeView.module.css
+++ b/packages/react/src/TreeView/TreeView.module.css
@@ -174,6 +174,10 @@
     display: flex;
     color: var(--fgColor-muted);
     grid-area: leadingAction;
+
+    & > button {
+      flex-shrink: 1;
+    }
   }
 
   .TreeViewItemLevelLine {
diff --git a/packages/react/src/TreeView/TreeView.tsx b/packages/react/src/TreeView/TreeView.tsx
index cb043e06f04..db2564f3a4a 100644
--- a/packages/react/src/TreeView/TreeView.tsx
+++ b/packages/react/src/TreeView/TreeView.tsx
@@ -242,6 +242,10 @@ const UlBox = toggleStyledComponent(
       display: flex;
       color: ${get('colors.fg.muted')};
       grid-area: leadingAction;
+
+      & > button {
+        flex-shrink: 1;
+      }
     }
 
     .PRIVATE_TreeView-item-level-line {