diff --git a/modules/system/defaults/NSGlobalDomain.nix b/modules/system/defaults/NSGlobalDomain.nix
index 5fb329e..023c06c 100644
--- a/modules/system/defaults/NSGlobalDomain.nix
+++ b/modules/system/defaults/NSGlobalDomain.nix
@@ -135,6 +135,14 @@ in {
       '';
     };
 
+    system.defaults.NSGlobalDomain.NSAutomaticWindowAnimationsEnabled = mkOption {
+      type = types.nullOr types.bool;
+      default = null;
+      description = ''
+        Whether to animate opening and closing of windows and popovers.  The default is true.
+      '';
+    };
+
     system.defaults.NSGlobalDomain.NSDisableAutomaticTermination = mkOption {
       type = types.nullOr types.bool;
       default = null;
diff --git a/tests/system-defaults-write.nix b/tests/system-defaults-write.nix
index 597e032..e959e50 100644
--- a/tests/system-defaults-write.nix
+++ b/tests/system-defaults-write.nix
@@ -14,6 +14,7 @@
   system.defaults.NSGlobalDomain.NSAutomaticPeriodSubstitutionEnabled = false;
   system.defaults.NSGlobalDomain.NSAutomaticQuoteSubstitutionEnabled = false;
   system.defaults.NSGlobalDomain.NSAutomaticSpellingCorrectionEnabled = false;
+  system.defaults.NSGlobalDomain.NSAutomaticWindowAnimationsEnabled = false;
   system.defaults.NSGlobalDomain.NSDisableAutomaticTermination = true;
   system.defaults.NSGlobalDomain.NSDocumentSaveNewDocumentsToCloud = false;
   system.defaults.NSGlobalDomain.NSNavPanelExpandedStateForSaveMode = true;
@@ -63,6 +64,7 @@
     grep "defaults write -g 'NSAutomaticPeriodSubstitutionEnabled' -bool NO" ${config.out}/activate-user
     grep "defaults write -g 'NSAutomaticQuoteSubstitutionEnabled' -bool NO" ${config.out}/activate-user
     grep "defaults write -g 'NSAutomaticSpellingCorrectionEnabled' -bool NO" ${config.out}/activate-user
+    grep "defaults write -g 'NSAutomaticWindowAnimationsEnabled' -bool NO" ${config.out}/activate-user
     grep "defaults write -g 'NSDisableAutomaticTermination' -bool YES" ${config.out}/activate-user
     grep "defaults write -g 'NSDocumentSaveNewDocumentsToCloud' -bool NO" ${config.out}/activate-user
     grep "defaults write -g 'NSNavPanelExpandedStateForSaveMode' -bool YES" ${config.out}/activate-user