diff --git a/src/add-to-project.ts b/src/add-to-project.ts
index 19c6715..4a2d11d 100644
--- a/src/add-to-project.ts
+++ b/src/add-to-project.ts
@@ -50,11 +50,16 @@ export async function addToProject(): Promise<void> {
       core.info(`Skipping issue ${issue?.number} because it doesn't match all the labels: ${labeled.join(', ')}`)
       return
     }
-  } else {
+  } else if (labelOperator === 'or') {
     if (labeled.length > 0 && !issueLabels.some(l => labeled.includes(l))) {
       core.info(`Skipping issue ${issue?.number} because it does not have one of the labels: ${labeled.join(', ')}`)
       return
     }
+  } else if (labelOperator === 'not') {
+    if (labeled.length > 0 && issueLabels.some(l => labeled.includes(l))) {
+      core.info(`Skipping issue $(issue?.number} because it contains one of the labels: $(labeled.join(', ')}`)
+      return
+    }
   }
 
   core.debug(`Project URL: ${projectUrl}`)