diff --git a/ql/src/queries/performance/DontUseGetAQlClass.ql b/ql/src/queries/performance/DontUseGetAQlClass.ql
new file mode 100644
index 00000000000..529a9263eec
--- /dev/null
+++ b/ql/src/queries/performance/DontUseGetAQlClass.ql
@@ -0,0 +1,22 @@
+/**
+ * @name Don't use getAQlClass.
+ * @description Any use of getAQlClass causes both compile-time and runtime to be significantly slower.
+ * @kind problem
+ * @problem.severity warning
+ * @id ql/dont-use-getAQlClass
+ * @tags performance
+ * @precision very-high
+ */
+
+import ql
+
+from Call call
+where
+  (
+    call.(PredicateCall).getPredicateName() = "getAQlClass" or
+    call.(MemberCall).getMemberName() = "getAQlClass"
+  ) and
+  not call.getLocation().getFile().getAbsolutePath().matches("%/" + ["meta", "test"] + "/%") and
+  not call.getLocation().getFile().getBaseName().toLowerCase() =
+    ["consistency.ql", "test.ql", "tst.ql", "tests.ql"]
+select call, "Don't use .getAQlClass"