diff --git a/stub/src/main/java/io/grpc/stub/ClientCalls.java b/stub/src/main/java/io/grpc/stub/ClientCalls.java
index e4d675487d8..13fb00d3b3e 100644
--- a/stub/src/main/java/io/grpc/stub/ClientCalls.java
+++ b/stub/src/main/java/io/grpc/stub/ClientCalls.java
@@ -58,8 +58,8 @@ public final class ClientCalls {
 
   @VisibleForTesting
   static boolean rejectRunnableOnExecutor =
-      Strings.isNullOrEmpty(System.getenv("GRPC_CLIENT_CALL_REJECT_RUNNABLE"))
-          || Boolean.parseBoolean(System.getenv("GRPC_CLIENT_CALL_REJECT_RUNNABLE"));
+      !Strings.isNullOrEmpty(System.getenv("GRPC_CLIENT_CALL_REJECT_RUNNABLE"))
+          && Boolean.parseBoolean(System.getenv("GRPC_CLIENT_CALL_REJECT_RUNNABLE"));
 
   // Prevent instantiation
   private ClientCalls() {}