diff --git a/pkg/build/gobuild.go b/pkg/build/gobuild.go
index fa63765a22..726d86dddd 100644
--- a/pkg/build/gobuild.go
+++ b/pkg/build/gobuild.go
@@ -690,6 +690,16 @@ func createBuildArgs(buildCfg Config) ([]string, error) {
 		args = append(args, fmt.Sprintf("-ldflags=%s", strings.Join(buildCfg.Ldflags, " ")))
 	}
 
+	// Reject any flags that attempt to set --toolexec (with or
+	// without =, with one or two -s)
+	for _, a := range args {
+		for _, d := range []string{"-", "--"} {
+			if a == d+"toolexec" || strings.HasPrefix(a, d+"toolexec=") {
+				return nil, fmt.Errorf("cannot set %s", a)
+			}
+		}
+	}
+
 	return args, nil
 }
 
diff --git a/test/build-configs/.ko.yaml b/test/build-configs/.ko.yaml
index c92d94308b..d8994ea965 100644
--- a/test/build-configs/.ko.yaml
+++ b/test/build-configs/.ko.yaml
@@ -19,3 +19,9 @@ builds:
 - id: bar-app
   dir: ./bar
   main: ./cmd
+- id: toolexec
+  dir: ./toolexec
+  main: ./cmd
+  flags:
+  - -toolexec
+  - go
diff --git a/test/build-configs/toolexec/cmd/main.go b/test/build-configs/toolexec/cmd/main.go
new file mode 100644
index 0000000000..2f0a0918ba
--- /dev/null
+++ b/test/build-configs/toolexec/cmd/main.go
@@ -0,0 +1,21 @@
+// Copyright 2022 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("toolexec")
+}
diff --git a/test/build-configs/toolexec/go.mod b/test/build-configs/toolexec/go.mod
new file mode 100644
index 0000000000..32d35d09ae
--- /dev/null
+++ b/test/build-configs/toolexec/go.mod
@@ -0,0 +1,17 @@
+// Copyright 2022 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+module example.com/toolexec
+
+go 1.16