diff --git a/nixos/modules/virtualisation/containers.nix b/nixos/modules/virtualisation/containers.nix
index 691ee2c136ec..09678ce9ea71 100644
--- a/nixos/modules/virtualisation/containers.nix
+++ b/nixos/modules/virtualisation/containers.nix
@@ -149,7 +149,7 @@ let
         --setenv PATH="$PATH" \
         ${optionalString cfg.ephemeral "--ephemeral"} \
         ${if cfg.additionalCapabilities != null && cfg.additionalCapabilities != [] then
-          ''--capability="${concatStringsSep " " cfg.additionalCapabilities}"'' else ""
+          ''--capability="${concatStringsSep "," cfg.additionalCapabilities}"'' else ""
         } \
         ${if cfg.tmpfs != null && cfg.tmpfs != [] then
           ''--tmpfs=${concatStringsSep " --tmpfs=" cfg.tmpfs}'' else ""