diff --git a/commands.go b/commands.go
index 30b0f17..338810e 100644
--- a/commands.go
+++ b/commands.go
@@ -174,6 +174,9 @@ func fnLoginGoogleCookies(ce *WrappedCommandEvent) {
 	if err != nil {
 		ce.Reply("Failed to parse cookies: %v", err)
 		return
+	} else if missingCookie := findMissingCookies(cookies); missingCookie != "" {
+		ce.Reply("Missing %s cookie", missingCookie)
+		return
 	}
 	ce.Redact()
 	err = ce.User.LoginGoogle(ce.Ctx, cookies, func(emoji string) {
diff --git a/provisioning.go b/provisioning.go
index cfafcda..e5d3412 100644
--- a/provisioning.go
+++ b/provisioning.go
@@ -20,6 +20,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"net/http"
 	_ "net/http/pprof"
 	"strings"
@@ -321,6 +322,15 @@ type RespGoogleLoginStart struct {
 	Emoji  string `json:"emoji"`
 }
 
+func findMissingCookies(cookies map[string]string) string {
+	for _, requiredCookie := range []string{"SID", "SSID", "HSID", "OSID", "APISID", "SAPISID"} {
+		if _, ok := cookies[requiredCookie]; !ok {
+			return requiredCookie
+		}
+	}
+	return ""
+}
+
 func (prov *ProvisioningAPI) GoogleLoginStart(w http.ResponseWriter, r *http.Request) {
 	userID := r.URL.Query().Get("user_id")
 	user := prov.bridge.GetUserByMXID(id.UserID(userID))
@@ -339,6 +349,20 @@ func (prov *ProvisioningAPI) GoogleLoginStart(w http.ResponseWriter, r *http.Req
 			ErrCode: "bad json",
 		})
 		return
+	} else if len(req.Cookies) == 0 {
+		log.Warn().Msg("No cookies in request")
+		jsonResponse(w, http.StatusBadRequest, Error{
+			Error:   "No cookies in request",
+			ErrCode: "missing cookies",
+		})
+		return
+	} else if missingCookie := findMissingCookies(req.Cookies); missingCookie != "" {
+		log.Warn().Msg("Missing cookies in request")
+		jsonResponse(w, http.StatusBadRequest, Error{
+			Error:   fmt.Sprintf("Missing %s cookie", missingCookie),
+			ErrCode: "missing cookies",
+		})
+		return
 	}
 	emoji, err := user.AsyncLoginGoogleStart(req.Cookies)
 	if err != nil {