diff --git a/ssl/test/bssl_shim.cc b/ssl/test/bssl_shim.cc
index 21497fd6..dccf0c98 100644
--- a/ssl/test/bssl_shim.cc
+++ b/ssl/test/bssl_shim.cc
@@ -1883,6 +1883,22 @@ static bool DoExchange(bssl::UniquePtr<SSL_SESSION> *out_session,
       return false;
     }
 
+    if (config->handshake_twice) {
+      do {
+        ret = SSL_do_handshake(ssl.get());
+      } while (config->async && RetryAsync(ssl.get(), ret));
+      if (ret != 1) {
+        return false;
+      }
+    }
+
+    // Skip the |config->async| logic as this should be a no-op.
+    if (config->no_op_extra_handshake &&
+        SSL_do_handshake(ssl.get()) != 1) {
+      fprintf(stderr, "Extra SSL_do_handshake was not a no-op.\n");
+      return false;
+    }
+
     // Reset the state to assert later that the callback isn't called in
     // renegotations.
     GetTestState(ssl.get())->got_new_session = false;
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index 3aa2c464..3bdb8656 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -10740,6 +10740,109 @@ func addECDSAKeyUsageTests() {
 	}
 }
 
+func addExtraHandshakeTests() {
+	// An extra SSL_do_handshake is normally a no-op. These tests use -async
+	// to ensure there is no transport I/O.
+	testCases = append(testCases, testCase{
+		testType: clientTest,
+		name:     "ExtraHandshake-Client-TLS12",
+		config: Config{
+			MinVersion: VersionTLS12,
+			MaxVersion: VersionTLS12,
+		},
+		flags: []string{
+			"-async",
+			"-no-op-extra-handshake",
+		},
+	})
+	testCases = append(testCases, testCase{
+		testType: serverTest,
+		name:     "ExtraHandshake-Server-TLS12",
+		config: Config{
+			MinVersion: VersionTLS12,
+			MaxVersion: VersionTLS12,
+		},
+		flags: []string{
+			"-async",
+			"-no-op-extra-handshake",
+		},
+	})
+	testCases = append(testCases, testCase{
+		testType: clientTest,
+		name:     "ExtraHandshake-Client-TLS13",
+		config: Config{
+			MinVersion: VersionTLS13,
+			MaxVersion: VersionTLS13,
+		},
+		flags: []string{
+			"-async",
+			"-no-op-extra-handshake",
+		},
+	})
+	testCases = append(testCases, testCase{
+		testType: serverTest,
+		name:     "ExtraHandshake-Server-TLS13",
+		config: Config{
+			MinVersion: VersionTLS13,
+			MaxVersion: VersionTLS13,
+		},
+		flags: []string{
+			"-async",
+			"-no-op-extra-handshake",
+		},
+	})
+
+	// An extra SSL_do_handshake is a no-op in server 0-RTT.
+	testCases = append(testCases, testCase{
+		testType: serverTest,
+		name:     "ExtraHandshake-Server-EarlyData-TLS13",
+		config: Config{
+			MaxVersion: VersionTLS13,
+			MinVersion: VersionTLS13,
+			Bugs: ProtocolBugs{
+				SendEarlyData:           [][]byte{{1, 2, 3, 4}},
+				ExpectEarlyDataAccepted: true,
+				ExpectHalfRTTData:       [][]byte{{254, 253, 252, 251}},
+			},
+		},
+		messageCount:  2,
+		resumeSession: true,
+		flags: []string{
+			"-async",
+			"-enable-early-data",
+			"-expect-accept-early-data",
+			"-no-op-extra-handshake",
+		},
+	})
+
+	// An extra SSL_do_handshake drives the handshake to completion in False
+	// Start. We test this by handshaking twice and asserting the False
+	// Start does not appear to happen. See AlertBeforeFalseStartTest for
+	// how the test works.
+	testCases = append(testCases, testCase{
+		testType: clientTest,
+		name:     "ExtraHandshake-FalseStart",
+		config: Config{
+			MaxVersion:   VersionTLS12,
+			CipherSuites: []uint16{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256},
+			NextProtos:   []string{"foo"},
+			Bugs: ProtocolBugs{
+				ExpectFalseStart:          true,
+				AlertBeforeFalseStartTest: alertAccessDenied,
+			},
+		},
+		flags: []string{
+			"-handshake-twice",
+			"-false-start",
+			"-advertise-alpn", "\x03foo",
+		},
+		shimWritesFirst:    true,
+		shouldFail:         true,
+		expectedError:      ":TLSV1_ALERT_ACCESS_DENIED:",
+		expectedLocalError: "tls: peer did not false start: EOF",
+	})
+}
+
 func worker(statusChan chan statusMsg, c chan *testCase, shimPath string, wg *sync.WaitGroup) {
 	defer wg.Done()
 
@@ -10866,6 +10969,7 @@ func main() {
 	addCertificateTests()
 	addRetainOnlySHA256ClientCertTests()
 	addECDSAKeyUsageTests()
+	addExtraHandshakeTests()
 
 	var wg sync.WaitGroup
 
diff --git a/ssl/test/test_config.cc b/ssl/test/test_config.cc
index 7e57543e..a8cf755c 100644
--- a/ssl/test/test_config.cc
+++ b/ssl/test/test_config.cc
@@ -128,6 +128,8 @@ const Flag<bool> kBoolFlags[] = {
   { "-expect-reject-early-data", &TestConfig::expect_reject_early_data },
   { "-expect-no-alpn", &TestConfig::expect_no_alpn },
   { "-expect-no-resume-alpn", &TestConfig::expect_no_resume_alpn },
+  { "-no-op-extra-handshake", &TestConfig::no_op_extra_handshake },
+  { "-handshake-twice", &TestConfig::handshake_twice },
 };
 
 const Flag<std::string> kStringFlags[] = {
diff --git a/ssl/test/test_config.h b/ssl/test/test_config.h
index fadd05eb..ef14f152 100644
--- a/ssl/test/test_config.h
+++ b/ssl/test/test_config.h
@@ -141,6 +141,8 @@ struct TestConfig {
   bool expect_session_id = false;
   bool expect_no_session_id = false;
   int expect_ticket_age_skew = 0;
+  bool no_op_extra_handshake = false;
+  bool handshake_twice = false;
 };
 
 bool ParseConfig(int argc, char **argv, TestConfig *out_config);