diff --git a/.changeset/fix-avatar-flex-shrink.md b/.changeset/fix-avatar-flex-shrink.md
new file mode 100644
index 0000000000..161a2327b6
--- /dev/null
+++ b/.changeset/fix-avatar-flex-shrink.md
@@ -0,0 +1,7 @@
+---
+'@backstage/ui': patch
+---
+
+Fixed `Avatar` becoming elliptical in flex layouts by preventing it from shrinking.
+
+**Affected components:** Avatar
diff --git a/packages/ui/src/components/Avatar/Avatar.module.css b/packages/ui/src/components/Avatar/Avatar.module.css
index 56c68c7100..1d0c4913be 100644
--- a/packages/ui/src/components/Avatar/Avatar.module.css
+++ b/packages/ui/src/components/Avatar/Avatar.module.css
@@ -30,6 +30,7 @@
     font-size: 1rem;
     line-height: 1;
     overflow: hidden;
+    flex-shrink: 0;
     height: 2rem;
     width: 2rem;
   }