diff --git a/auth/auth.go b/auth/auth.go
index d6299611..8884bf68 100644
--- a/auth/auth.go
+++ b/auth/auth.go
@@ -21,6 +21,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"runtime"
 	"strings"
 	"time"
 
@@ -137,6 +138,7 @@ func NewClient(ctx context.Context, conf *internal.AuthConfig) (*Client, error)
 	hc.CreateErrFn = handleHTTPError
 	hc.Opts = []internal.HTTPOption{
 		internal.WithHeader("X-Client-Version", fmt.Sprintf("Go/Admin/%s", conf.Version)),
+		internal.WithHeader("x-goog-api-client", fmt.Sprintf("gl-go/%s fire-admin/%s", runtime.Version(), conf.Version)),
 	}
 
 	baseURL := defaultAuthURL
diff --git a/auth/auth_test.go b/auth/auth_test.go
index 30fbde88..c0c8f91f 100644
--- a/auth/auth_test.go
+++ b/auth/auth_test.go
@@ -23,6 +23,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"runtime"
 	"strings"
 	"syscall"
 	"testing"
@@ -1451,6 +1452,12 @@ func checkBaseClient(client *Client, wantProjectID string) error {
 		return fmt.Errorf("version = %q; want = %q", version, wantVersion)
 	}
 
+	xGoogApiClientHeader := req.Header.Get("x-goog-api-client")
+	wantXGoogApiClientHeader := fmt.Sprintf("gl-go/%s fire-admin/%s", runtime.Version(), testVersion)
+	if xGoogApiClientHeader != wantXGoogApiClientHeader {
+		return fmt.Errorf("x-goog-api-client header = %q; want = %q", xGoogApiClientHeader, wantXGoogApiClientHeader)
+	}
+
 	return nil
 }
 
diff --git a/auth/user_mgt_test.go b/auth/user_mgt_test.go
index ffa48655..55cfd3a4 100644
--- a/auth/user_mgt_test.go
+++ b/auth/user_mgt_test.go
@@ -24,6 +24,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"reflect"
+	"runtime"
 	"sort"
 	"strconv"
 	"strings"
@@ -2315,6 +2316,12 @@ func echoServer(resp interface{}, t *testing.T) *mockAuthServer {
 			t.Errorf("X-Client-Version header = %q; want: %q", gh, wh)
 		}
 
+		gh = r.Header.Get("x-goog-api-client")
+		wh = fmt.Sprintf("gl-go/%s fire-admin/%s", runtime.Version(), testVersion)
+		if gh != wh {
+			t.Errorf("x-goog-api-client header = %q; want: %q", gh, wh)
+		}
+
 		for k, v := range s.Header {
 			w.Header().Set(k, v)
 		}
diff --git a/messaging/messaging.go b/messaging/messaging.go
index 2a846166..12271a9a 100644
--- a/messaging/messaging.go
+++ b/messaging/messaging.go
@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"net/http"
 	"regexp"
+	"runtime"
 	"strconv"
 	"strings"
 	"time"
@@ -897,6 +898,7 @@ func newFCMClient(hc *http.Client, conf *internal.MessagingConfig, messagingEndp
 	client.Opts = []internal.HTTPOption{
 		internal.WithHeader(apiFormatVersionHeader, apiFormatVersion),
 		internal.WithHeader(firebaseClientHeader, version),
+		internal.WithHeader("x-goog-api-client", fmt.Sprintf("gl-go/%s fire-admin/%s", runtime.Version(), conf.Version)),
 	}
 
 	return &fcmClient{
diff --git a/messaging/messaging_test.go b/messaging/messaging_test.go
index 7421fb7e..a782da8c 100644
--- a/messaging/messaging_test.go
+++ b/messaging/messaging_test.go
@@ -21,6 +21,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"reflect"
+	"runtime"
 	"testing"
 	"time"
 
@@ -1394,6 +1395,10 @@ func checkFCMRequest(t *testing.T, b []byte, tr *http.Request, want map[string]i
 	if h := tr.Header.Get("X-FIREBASE-CLIENT"); h != clientVersion {
 		t.Errorf("X-FIREBASE-CLIENT = %q; want = %q", h, clientVersion)
 	}
+	xGoogApiClientHeader := "gl-go/" + runtime.Version() + " fire-admin/" + testMessagingConfig.Version
+	if h := tr.Header.Get("x-goog-api-client"); h != xGoogApiClientHeader {
+		t.Errorf("x-goog-api-client header = %q; want = %q", h, xGoogApiClientHeader)
+	}
 }
 
 var httpErrors = []struct {