diff --git a/.changeset/sweet-icons-sneeze.md b/.changeset/sweet-icons-sneeze.md
new file mode 100644
index 0000000000..b12424c7a8
--- /dev/null
+++ b/.changeset/sweet-icons-sneeze.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-react': patch
+---
+
+Fix `EntityTypeFilter` so generating available types is case insensitive
diff --git a/plugins/catalog-react/src/hooks/useEntityTypeFilter.tsx b/plugins/catalog-react/src/hooks/useEntityTypeFilter.tsx
index 8e8c1b24d7..464531a4d9 100644
--- a/plugins/catalog-react/src/hooks/useEntityTypeFilter.tsx
+++ b/plugins/catalog-react/src/hooks/useEntityTypeFilter.tsx
@@ -96,7 +96,13 @@ export function useEntityTypeFilter(): {
     }
 
     // Sort by facet count descending, so the most common types appear on top
-    const newTypes = sortBy(facets, f => -f.count).map(f => f.value);
+    const newTypes = [
+      ...new Set(
+        sortBy(facets, f => -f.count).map(f =>
+          f.value.toLocaleLowerCase('en-US'),
+        ),
+      ),
+    ];
     setAvailableTypes(newTypes);
 
     // Update type filter to only valid values when the list of available types has changed