diff --git a/.changeset/honest-countries-deny.md b/.changeset/honest-countries-deny.md
new file mode 100644
index 0000000000..14c9094592
--- /dev/null
+++ b/.changeset/honest-countries-deny.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-jenkins-backend': patch
+---
+
+Fix handling of slashes in branch names
diff --git a/plugins/jenkins-backend/src/service/jenkinsApi.test.ts b/plugins/jenkins-backend/src/service/jenkinsApi.test.ts
index 57ce2dbed4..c89a3866c7 100644
--- a/plugins/jenkins-backend/src/service/jenkinsApi.test.ts
+++ b/plugins/jenkins-backend/src/service/jenkinsApi.test.ts
@@ -173,6 +173,7 @@ describe('JenkinsApi', () => {
           'foo',
           'bar',
           'catpants',
+          'with-a/slash',
         ]);
 
         expect(mockedJenkins).toHaveBeenCalledWith({
@@ -192,6 +193,10 @@ describe('JenkinsApi', () => {
           name: `${jenkinsInfo.jobFullName}/catpants`,
           tree: expect.anything(),
         });
+        expect(mockedJenkinsClient.job.get).toHaveBeenCalledWith({
+          name: `${jenkinsInfo.jobFullName}/with-a%2Fslash`,
+          tree: expect.anything(),
+        });
         expect(result).toHaveLength(1);
       });
     });
diff --git a/plugins/jenkins-backend/src/service/jenkinsApi.ts b/plugins/jenkins-backend/src/service/jenkinsApi.ts
index ef4ddc47b0..e14437fa68 100644
--- a/plugins/jenkins-backend/src/service/jenkinsApi.ts
+++ b/plugins/jenkins-backend/src/service/jenkinsApi.ts
@@ -80,7 +80,7 @@ export class JenkinsApiImpl {
       const job = await Promise.any(
         branches.map(branch =>
           client.job.get({
-            name: `${jenkinsInfo.jobFullName}/${branch}`,
+            name: `${jenkinsInfo.jobFullName}/${encodeURIComponent(branch)}`,
             tree: JenkinsApiImpl.jobTreeSpec.replace(/\s/g, ''),
           }),
         ),