diff --git a/modules/core/xdg.nix b/modules/core/xdg.nix
index ac47b31..d4b99a1 100644
--- a/modules/core/xdg.nix
+++ b/modules/core/xdg.nix
@@ -2,6 +2,7 @@
 {
   config = {
     hm.xdg.enable = true;
+    hm.xdg.mimeApps.enable = true;
     hm.xdg.userDirs = rec {
       enable = true;
       createDirectories = true;
diff --git a/modules/software/system/mpv.nix b/modules/software/system/mpv.nix
index 163a60b..9ca7c87 100644
--- a/modules/software/system/mpv.nix
+++ b/modules/software/system/mpv.nix
@@ -38,5 +38,27 @@ in {
         visualizer
       ];
     };
+
+    # https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/MIME_types/Common_types
+    hm.xdg.mimeApps.defaultApplications = {
+      "audio/3gpp" = [ "mpv.desktop" ]; # 3gp
+      "audio/3gpp2" = [ "mpv.desktop" ]; # 3g2
+      "audio/aac" = [ "mpv.desktop" ];
+      # `midi`: unsupported
+      "audio/mpeg" = [ "mpv.desktop" ]; # mp3
+      "audio/ogg" = [ "mpv.desktop" ];
+      "audio/wav" = [ "mpv.desktop" ];
+      "audio/webm" = [ "mpv.desktop" ]; # weba
+      "video/3gpp" = [ "mpv.desktop" ]; # 3gp
+      "video/3gpp2" = [ "mpv.desktop" ]; # 3g2
+      "video/x-msvideo" = [ "mpv.desktop" ]; # avi
+      "video/x-matroska" = [ "mpv.desktop" ]; # mkv
+      "video/quicktime" = [ "mpv.desktop" ]; # mov
+      "video/mp4" = [ "mpv.desktop" ];
+      "video/mpeg" = [ "mpv.desktop" ];
+      "video/ogg" = [ "mpv.desktop" ]; # ogv
+      # `ts`: not as commonly used as typescript
+      "video/webm" = [ "mpv.desktop" ];
+    };
   };
 }