diff --git a/.changeset/curly-news-report.md b/.changeset/curly-news-report.md
new file mode 100644
index 0000000000..9463b8e72f
--- /dev/null
+++ b/.changeset/curly-news-report.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-kubernetes-backend': patch
+---
+
+Fixed a bug where the proxy handler did not properly handle a missing header
diff --git a/plugins/kubernetes-backend/src/service/KubernetesProxy.ts b/plugins/kubernetes-backend/src/service/KubernetesProxy.ts
index 8cd5f0159a..0d6370ddc5 100644
--- a/plugins/kubernetes-backend/src/service/KubernetesProxy.ts
+++ b/plugins/kubernetes-backend/src/service/KubernetesProxy.ts
@@ -182,8 +182,9 @@ export class KubernetesProxy {
             )?.toString(),
           };
 
-          const authHeader = req.header(HEADER_KUBERNETES_AUTH);
-          if (authHeader) {
+          const authHeader =
+            req.headers[HEADER_KUBERNETES_AUTH.toLocaleLowerCase('en-US')];
+          if (typeof authHeader === 'string') {
             req.headers.authorization = authHeader;
           } else {
             // Map Backstage-Kubernetes-Authorization-X-X headers to a KubernetesRequestAuth object