diff --git a/.changeset/gorgeous-dolphins-compare.md b/.changeset/gorgeous-dolphins-compare.md
new file mode 100644
index 00000000000..3087c1fdb07
--- /dev/null
+++ b/.changeset/gorgeous-dolphins-compare.md
@@ -0,0 +1,5 @@
+---
+'@primer/react': patch
+---
+
+Fix MarkdownEditor fullHeight support
diff --git a/src/drafts/MarkdownEditor/MarkdownEditor.tsx b/src/drafts/MarkdownEditor/MarkdownEditor.tsx
index 08ce856eeac..03bcd6017b0 100644
--- a/src/drafts/MarkdownEditor/MarkdownEditor.tsx
+++ b/src/drafts/MarkdownEditor/MarkdownEditor.tsx
@@ -373,7 +373,7 @@ const MarkdownEditor = forwardRef<MarkdownEditorHandle, MarkdownEditorProps>(
         <fieldset
           aria-disabled={disabled /* if we set disabled={true}, we can't enable the buttons that should be enabled */}
           aria-describedby={describedBy ? `${descriptionId} ${describedBy}` : descriptionId}
-          style={{appearance: 'none', border: 'none', minInlineSize: 'auto'}}
+          style={{appearance: 'none', border: 'none', minInlineSize: 'auto', height: fullHeight ? '100%' : undefined}}
         >
           <FormattingTools ref={formattingToolsRef} forInputId={id} />
           <div style={{display: 'none'}}>{childrenWithoutSlots}</div>