diff --git a/changelog/unreleased/index-all-spaces.md b/changelog/unreleased/index-all-spaces.md
new file mode 100644
index 00000000000..c07b1dbab00
--- /dev/null
+++ b/changelog/unreleased/index-all-spaces.md
@@ -0,0 +1,5 @@
+Enhancement: Allow reindexing all spaces
+
+Adds a `--all-spaces` flag to the `ocis search index` command to allow reindexing all spaces at once.
+
+https://github.com/owncloud/ocis/pull/9456
diff --git a/services/search/pkg/command/index.go b/services/search/pkg/command/index.go
index e743a886a55..39dc33618e3 100644
--- a/services/search/pkg/command/index.go
+++ b/services/search/pkg/command/index.go
@@ -2,6 +2,7 @@ package command
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"time"
 
@@ -25,22 +26,23 @@ func Index(cfg *config.Config) *cli.Command {
 		Aliases:  []string{"i"},
 		Flags: []cli.Flag{
 			&cli.StringFlag{
-				Name:     "space",
-				Aliases:  []string{"s"},
-				Required: true,
-				Usage:    "the id of the space to travers and index the files of",
+				Name:    "space",
+				Aliases: []string{"s"},
+				Usage:   "the id of the space to travers and index the files of. This or --all-spaces is required.",
 			},
-			&cli.StringFlag{
-				Name:     "user",
-				Aliases:  []string{"u"},
-				Required: true,
-				Usage:    "the username of the user that shall be used to access the files",
+			&cli.BoolFlag{
+				Name:  "all-spaces",
+				Usage: "index all spaces instead. This or --space is required.",
 			},
 		},
-		Before: func(c *cli.Context) error {
+		Before: func(_ *cli.Context) error {
 			return configlog.ReturnFatal(parser.ParseConfig(cfg))
 		},
 		Action: func(ctx *cli.Context) error {
+			if ctx.String("space") == "" && !ctx.Bool("all-spaces") {
+				return errors.New("either --space or --all-spaces is required")
+			}
+
 			traceProvider, err := tracing.GetServiceTraceProvider(cfg.Tracing, cfg.Service.Name)
 			if err != nil {
 				return err
@@ -57,7 +59,6 @@ func Index(cfg *config.Config) *cli.Command {
 			c := searchsvc.NewSearchProviderService("com.owncloud.api.search", grpcClient)
 			_, err = c.IndexSpace(context.Background(), &searchsvc.IndexSpaceRequest{
 				SpaceId: ctx.String("space"),
-				UserId:  ctx.String("user"),
 			}, func(opts *client.CallOptions) { opts.RequestTimeout = 10 * time.Minute })
 			if err != nil {
 				fmt.Println("failed to index space: " + err.Error())
diff --git a/services/search/pkg/service/grpc/v0/service.go b/services/search/pkg/service/grpc/v0/service.go
index cfe461dea6b..88cb5c16ab3 100644
--- a/services/search/pkg/service/grpc/v0/service.go
+++ b/services/search/pkg/service/grpc/v0/service.go
@@ -6,7 +6,9 @@ import (
 	"fmt"
 	"time"
 
+	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	user "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
+	rpc "github.com/cs3org/go-cs3apis/cs3/rpc/v1beta1"
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
 	"github.com/cs3org/reva/v2/pkg/errtypes"
@@ -14,6 +16,7 @@ import (
 	"github.com/cs3org/reva/v2/pkg/rgrpc/todo/pool"
 	"github.com/cs3org/reva/v2/pkg/token"
 	"github.com/cs3org/reva/v2/pkg/token/manager/jwt"
+	"github.com/cs3org/reva/v2/pkg/utils"
 	"github.com/jellydator/ttlcache/v2"
 	merrors "go-micro.dev/v4/errors"
 	"go-micro.dev/v4/metadata"
@@ -23,6 +26,7 @@ import (
 	"github.com/owncloud/ocis/v2/ocis-pkg/registry"
 	v0 "github.com/owncloud/ocis/v2/protogen/gen/ocis/messages/search/v0"
 	searchsvc "github.com/owncloud/ocis/v2/protogen/gen/ocis/services/search/v0"
+	"github.com/owncloud/ocis/v2/services/search/pkg/config"
 	"github.com/owncloud/ocis/v2/services/search/pkg/content"
 	"github.com/owncloud/ocis/v2/services/search/pkg/engine"
 	"github.com/owncloud/ocis/v2/services/search/pkg/query/bleve"
@@ -114,6 +118,8 @@ func NewHandler(opts ...Option) (searchsvc.SearchProviderHandler, func(), error)
 		searcher:     ss,
 		cache:        cache,
 		tokenManager: tokenManager,
+		gws:          selector,
+		cfg:          cfg,
 	}, teardown, nil
 }
 
@@ -124,6 +130,8 @@ type Service struct {
 	searcher     search.Searcher
 	cache        *ttlcache.Cache
 	tokenManager token.Manager
+	gws          *pool.Selector[gateway.GatewayAPIClient]
+	cfg          *config.Config
 }
 
 // Search handles the search
@@ -171,8 +179,38 @@ func (s Service) Search(ctx context.Context, in *searchsvc.SearchRequest, out *s
 }
 
 // IndexSpace (re)indexes all resources of a given space.
-func (s Service) IndexSpace(ctx context.Context, in *searchsvc.IndexSpaceRequest, _ *searchsvc.IndexSpaceResponse) error {
-	return s.searcher.IndexSpace(&provider.StorageSpaceId{OpaqueId: in.SpaceId})
+func (s Service) IndexSpace(_ context.Context, in *searchsvc.IndexSpaceRequest, _ *searchsvc.IndexSpaceResponse) error {
+	if in.GetSpaceId() != "" {
+		return s.searcher.IndexSpace(&provider.StorageSpaceId{OpaqueId: in.GetSpaceId()})
+	}
+
+	// index all spaces instead
+	gwc, err := s.gws.Next()
+	if err != nil {
+		return err
+	}
+
+	ctx, err := utils.GetServiceUserContext(s.cfg.ServiceAccount.ServiceAccountID, gwc, s.cfg.ServiceAccount.ServiceAccountSecret)
+	if err != nil {
+		return err
+	}
+
+	resp, err := gwc.ListStorageSpaces(ctx, &provider.ListStorageSpacesRequest{})
+	if err != nil {
+		return err
+	}
+
+	if resp.GetStatus().GetCode() != rpc.Code_CODE_OK {
+		return errors.New(resp.GetStatus().GetMessage())
+	}
+
+	for _, space := range resp.GetStorageSpaces() {
+		if err := s.searcher.IndexSpace(space.GetId()); err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
 // FromCache pulls a search result from cache