diff --git a/store.go b/store.go
index 4a9ca96..5575ddc 100644
--- a/store.go
+++ b/store.go
@@ -56,6 +56,7 @@ type ShareStore interface {
 	GetShares() ([]Share, error)
 	GetShareUsers(share Share) ([]ShareUser, error)
 	GetShareLogins(share Share, username string) ([]Login, error)
+	GetShareAccess(share Share, username string) (ShareRole, error)
 
 	FindShareByLogin(username, loginName string) (LoginShare, error)
 	FindSharesByUser(username string) ([]UserShare, error)
@@ -384,6 +385,30 @@ func (store *DBStore) AddUserToShare(share Share, username string, role ShareRol
 	})
 }
 
+func (store *DBStore) GetShareAccess(share Share, username string) (ShareRole, error) {
+	if strings.Contains(username, ":") {
+		return "", ErrInvalidUsername
+	}
+
+	var shareRole ShareRole
+
+	err := store.db.View(func(tx *buntdb.Tx) error {
+		if _, err := tx.Get(share.key()); err != nil {
+			return ErrShareNotFound
+		}
+		if val, err := tx.Get(share.userKey(username)); err == buntdb.ErrNotFound {
+			return ErrUserNotFound
+		} else if err != nil {
+			return fmt.Errorf("cannot get user: %w", err)
+		} else {
+			shareRole = ShareRole(val)
+		}
+		return nil
+	})
+
+	return shareRole, err
+}
+
 func (store *DBStore) removeUserFromShare(tx *buntdb.Tx, share Share, username string) error {
 	var logins []string
 	loginsPrefix := share.loginKey(username, "")
diff --git a/store_test.go b/store_test.go
index 030f14d..4d3612e 100644
--- a/store_test.go
+++ b/store_test.go
@@ -244,6 +244,23 @@ func TestStoreShareHandling(t *testing.T) {
 				}
 			})
 
+			t.Run("can get share access", func(t *testing.T) {
+				shareRole, err := store.GetShareAccess(share1, user1.Username)
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+				if shareRole != ShareRoleAdmin {
+					t.Errorf("unexpected role: %s", shareRole)
+				}
+			})
+
+			t.Run("cannot get share access if user has none", func(t *testing.T) {
+				_, err := store.GetShareAccess(share2, user1.Username)
+				if err != ErrUserNotFound {
+					t.Errorf("unexpected error: %v", err)
+				}
+			})
+
 			t.Run("can list users", func(t *testing.T) {
 				users, err := store.GetShareUsers(share1)
 				if err != nil {
diff --git a/webadmin.go b/webadmin.go
index ff8f312..146766b 100644
--- a/webadmin.go
+++ b/webadmin.go
@@ -57,6 +57,7 @@ type sessionContext struct {
 	h         *webAdminHandler
 	w         http.ResponseWriter
 	r         *http.Request
+	user      User
 	baseModel map[string]interface{}
 }
 
@@ -181,6 +182,11 @@ func newWebAdminHandler(app *app) *webAdminHandler {
 	ar.Get("/users", func(w http.ResponseWriter, r *http.Request) {
 		sessionContext := h.buildSessionContext(w, r)
 
+		if sessionContext.user.Role != GlobalRoleAdmin {
+			sessionContext.Unauthorized()
+			return
+		}
+
 		users, err := app.userStore.GetUsers()
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -194,6 +200,11 @@ func newWebAdminHandler(app *app) *webAdminHandler {
 	ar.Get("/shares", func(w http.ResponseWriter, r *http.Request) {
 		sessionContext := h.buildSessionContext(w, r)
 
+		if sessionContext.user.Role != GlobalRoleAdmin {
+			sessionContext.Unauthorized()
+			return
+		}
+
 		shares, err := app.shareStore.GetShares()
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -224,12 +235,20 @@ func newWebAdminHandler(app *app) *webAdminHandler {
 		r.Get("/", func(w http.ResponseWriter, r *http.Request) {
 			sessionContext := h.buildSessionContext(w, r)
 
-			shareId := r.URL.Query().Get("share")
-			if shareId == "" {
-				http.Error(w, "invalid share id", http.StatusBadRequest)
+			share, err := app.shareStore.GetShare(r.URL.Query().Get("share"))
+			if err != nil {
+				sessionContext.RenderError(template.HTML("Internal error: "+err.Error()), "")
 				return
 			}
 
+			if sessionContext.user.Role != GlobalRoleAdmin {
+				shareRole, err := app.shareStore.GetShareAccess(share, sessionContext.user.Username)
+				if err != nil || shareRole != ShareRoleAdmin {
+					sessionContext.Unauthorized()
+					return
+				}
+			}
+
 			users, err := app.userStore.GetUsers()
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -237,7 +256,7 @@ func newWebAdminHandler(app *app) *webAdminHandler {
 			}
 
 			sessionContext.RenderPage(h.tplShareAddUser, map[string]interface{}{
-				"ShareId": shareId,
+				"ShareId": share.UUID,
 				"Users":   users,
 			})
 		})
@@ -246,12 +265,19 @@ func newWebAdminHandler(app *app) *webAdminHandler {
 
 			returnURL := "share-add-user?share=" + r.FormValue("share")
 
-			shareId, err := uuid.FromString(r.FormValue("share"))
+			share, err := app.shareStore.GetShare(r.FormValue("share"))
 			if err != nil {
 				sessionContext.RenderError(template.HTML("Internal error: "+err.Error()), "")
 				return
 			}
-			share := Share{UUID: shareId}
+
+			if sessionContext.user.Role != GlobalRoleAdmin {
+				shareRole, err := app.shareStore.GetShareAccess(share, sessionContext.user.Username)
+				if err != nil || shareRole != ShareRoleAdmin {
+					sessionContext.Unauthorized()
+					return
+				}
+			}
 
 			user, err := app.userStore.GetUser(r.FormValue("user"))
 			if err == ErrUserNotFound {
@@ -276,12 +302,19 @@ func newWebAdminHandler(app *app) *webAdminHandler {
 
 		returnURL := "shares"
 
-		shareId, err := uuid.FromString(r.FormValue("share"))
+		share, err := app.shareStore.GetShare(r.FormValue("share"))
 		if err != nil {
 			sessionContext.RenderError(template.HTML("Internal error: "+err.Error()), "")
 			return
 		}
-		share := Share{UUID: shareId}
+
+		if sessionContext.user.Role != GlobalRoleAdmin {
+			shareRole, err := app.shareStore.GetShareAccess(share, sessionContext.user.Username)
+			if err != nil || shareRole != ShareRoleAdmin {
+				sessionContext.Unauthorized()
+				return
+			}
+		}
 
 		err = app.shareStore.RemoveUserFromShare(share, r.FormValue("user"))
 		if err != nil {
@@ -325,6 +358,14 @@ func newWebAdminHandler(app *app) *webAdminHandler {
 			return
 		}
 
+		if sessionContext.user.Role != GlobalRoleAdmin {
+			shareRole, err := app.shareStore.GetShareAccess(share, sessionContext.user.Username)
+			if err != nil || shareRole != ShareRoleAdmin {
+				sessionContext.Unauthorized()
+				return
+			}
+		}
+
 		message := fmt.Sprintf(`You are about to delete the share %s (%s).<br/>
 This will delete all data permanently.<br/><br/>
 Are you sure you want to continue?`, share.UUID, share.Name)
@@ -357,6 +398,7 @@ func (h *webAdminHandler) buildSessionContext(w http.ResponseWriter, r *http.Req
 	}
 	sessionUser := userFromContext(r)
 	if sessionUser != nil {
+		sessionContext.user = *sessionUser
 		sessionContext.baseModel["SessionUser"] = sessionUser
 	}
 	return sessionContext
@@ -387,6 +429,10 @@ func (s *sessionContext) RenderError(msg template.HTML, returnURL string) {
 	s.RenderPage(s.h.tplError, model)
 }
 
+func (s *sessionContext) Unauthorized() {
+	http.Error(s.w, http.StatusText(http.StatusForbidden), http.StatusForbidden)
+}
+
 func (s *sessionContext) RequestConfirmation(msg template.HTML, returnURL string) int {
 	if s.r.FormValue("_yes") != "" {
 		return confirmAccepted