diff --git a/doc/go1.15.html b/doc/go1.15.html
index b4319874c9b..aa951eefad2 100644
--- a/doc/go1.15.html
+++ b/doc/go1.15.html
@@ -86,6 +86,13 @@ TODO
       that reports the time at which the test binary will have exceeded its
       timeout.
     </p>
+    <p><!-- golang.org/issue/34129 -->
+      A <code>TestMain</code> function is no longer required to call
+      <code>os.Exit</code>. If a <code>TestMain</code> function returns,
+      the test binary will call <code>os.Exit</code> with the value returned
+      by <code>m.Run</code>.
+    </p>
+  </dd>
 </dl><!-- testing -->
 
 <h3 id="minor_library_changes">Minor changes to the library</h3>
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index fefc7d2e307..866e0e567f2 100644
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -26,6 +26,7 @@ import (
 var TestMainDeps = []string{
 	// Dependencies for testmain.
 	"os",
+	"reflect",
 	"testing",
 	"testing/internal/testdeps",
 }
@@ -612,8 +613,9 @@ var testmainTmpl = lazytemplate.New("main", `
 package main
 
 import (
-{{if not .TestMain}}
 	"os"
+{{if .TestMain}}
+	"reflect"
 {{end}}
 	"testing"
 	"testing/internal/testdeps"
@@ -704,6 +706,7 @@ func main() {
 	m := testing.MainStart(testdeps.TestDeps{}, tests, benchmarks, examples)
 {{with .TestMain}}
 	{{.Package}}.{{.Name}}(m)
+	os.Exit(int(reflect.ValueOf(m).Elem().FieldByName("exitCode").Int()))
 {{else}}
 	os.Exit(m.Run())
 {{end}}
diff --git a/src/cmd/go/testdata/script/list_importmap.txt b/src/cmd/go/testdata/script/list_importmap.txt
index 52ee6028f5b..f424b9814c6 100644
--- a/src/cmd/go/testdata/script/list_importmap.txt
+++ b/src/cmd/go/testdata/script/list_importmap.txt
@@ -16,7 +16,7 @@ go list -deps -test -f '{{.ImportPath}} MAP: {{.ImportMap}}{{"\n"}}{{.ImportPath
 stdout '^flag \[fmt\.test\] MAP: map\[fmt:fmt \[fmt\.test\]\]'
 stdout '^fmt\.test MAP: map\[(.* )?testing:testing \[fmt\.test\]'
 ! stdout '^fmt\.test MAP: map\[(.* )?os:'
-stdout '^fmt\.test IMPORT: \[fmt \[fmt\.test\] fmt_test \[fmt\.test\] os testing \[fmt\.test\] testing/internal/testdeps \[fmt\.test\]\]'
+stdout '^fmt\.test IMPORT: \[fmt \[fmt\.test\] fmt_test \[fmt\.test\] os reflect testing \[fmt\.test\] testing/internal/testdeps \[fmt\.test\]\]'
 
 
 -- a/b/b.go --
diff --git a/src/cmd/go/testdata/script/list_test_imports.txt b/src/cmd/go/testdata/script/list_test_imports.txt
index b2a6bc45f9e..0342eba8623 100644
--- a/src/cmd/go/testdata/script/list_test_imports.txt
+++ b/src/cmd/go/testdata/script/list_test_imports.txt
@@ -16,6 +16,6 @@ package b_test; import _ "a"
 -- imports.txt --
 a: b
 b:
-b.test: b [b.test], b_test [b.test], os, testing, testing/internal/testdeps
+b.test: b [b.test], b_test [b.test], os, reflect, testing, testing/internal/testdeps
 b [b.test]:
 b_test [b.test]: a [b.test]
diff --git a/src/cmd/go/testdata/script/test_main.txt b/src/cmd/go/testdata/script/test_main.txt
index e255eab7e11..25d02e4465c 100644
--- a/src/cmd/go/testdata/script/test_main.txt
+++ b/src/cmd/go/testdata/script/test_main.txt
@@ -12,6 +12,10 @@ stdout '^ok.*\[no tests to run\]'
 ! go test standalone_main_wrong_test.go
 stderr 'wrong signature for TestMain, must be: func TestMain\(m \*testing.M\)'
 
+# Test TestMain does not call os.Exit (Issue #34129)
+! go test standalone_testmain_not_call_os_exit_test.go
+! stdout '^ok'
+
 -- standalone_main_normal_test.go --
 // Copyright 2017 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -64,3 +68,25 @@ func TestMain(m *testing.M) {
 	}
 	os.Exit(m.Run())
 }
+-- standalone_testmain_not_call_os_exit_test.go --
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package standalone_testmain_not_call_os_exit_test
+
+import (
+	"testing"
+)
+
+func TestWillFail(t *testing.T) {
+	t.Error("this test will fail.")
+}
+
+func TestMain(m *testing.M) {
+	defer func() {
+		recover()
+	}()
+	exit := m.Run()
+	panic(exit)
+}
diff --git a/src/testing/testing.go b/src/testing/testing.go
index 83cd72fff33..039d3e62090 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -217,10 +217,11 @@
 //
 // then the generated test will call TestMain(m) instead of running the tests
 // directly. TestMain runs in the main goroutine and can do whatever setup
-// and teardown is necessary around a call to m.Run. It should then call
-// os.Exit with the result of m.Run. When TestMain is called, flag.Parse has
-// not been run. If TestMain depends on command-line flags, including those
-// of the testing package, it should call flag.Parse explicitly.
+// and teardown is necessary around a call to m.Run. m.Run will return an exit
+// status that may be passed to os.Exit. If TestMain returns, the test wrapper
+// will pass the result of m.Run to os.Exit itself. When TestMain is called,
+// flag.Parse has not been run. If TestMain depends on command-line flags,
+// including those of the testing package, it should call flag.Parse explicitly.
 //
 // A simple implementation of TestMain is:
 //
@@ -1148,6 +1149,10 @@ type M struct {
 	afterOnce sync.Once
 
 	numRun int
+
+	// value to pass to os.Exit, the outer test func main
+	// harness calls os.Exit with this code. See #34129.
+	exitCode int
 }
 
 // testDeps is an internal interface of functionality that is
@@ -1178,7 +1183,11 @@ func MainStart(deps testDeps, tests []InternalTest, benchmarks []InternalBenchma
 }
 
 // Run runs the tests. It returns an exit code to pass to os.Exit.
-func (m *M) Run() int {
+func (m *M) Run() (code int) {
+	defer func() {
+		code = m.exitCode
+	}()
+
 	// Count the number of calls to m.Run.
 	// We only ever expected 1, but we didn't enforce that,
 	// and now there are tests in the wild that call m.Run multiple times.
@@ -1193,12 +1202,14 @@ func (m *M) Run() int {
 	if *parallel < 1 {
 		fmt.Fprintln(os.Stderr, "testing: -parallel can only be given a positive integer")
 		flag.Usage()
-		return 2
+		m.exitCode = 2
+		return
 	}
 
 	if len(*matchList) != 0 {
 		listTests(m.deps.MatchString, m.tests, m.benchmarks, m.examples)
-		return 0
+		m.exitCode = 0
+		return
 	}
 
 	parseCpuList()
@@ -1215,11 +1226,13 @@ func (m *M) Run() int {
 	}
 	if !testOk || !exampleOk || !runBenchmarks(m.deps.ImportPath(), m.deps.MatchString, m.benchmarks) || race.Errors() > 0 {
 		fmt.Println("FAIL")
-		return 1
+		m.exitCode = 1
+		return
 	}
 
 	fmt.Println("PASS")
-	return 0
+	m.exitCode = 0
+	return
 }
 
 func (t *T) report() {