diff --git a/pkgs/development/python-modules/tree-sitter-grammars/default.nix b/pkgs/development/python-modules/tree-sitter-grammars/default.nix
index 8abe7bae8221..4bf53a9e134a 100644
--- a/pkgs/development/python-modules/tree-sitter-grammars/default.nix
+++ b/pkgs/development/python-modules/tree-sitter-grammars/default.nix
@@ -12,8 +12,20 @@
   grammarDrv,
 }:
 let
-  inherit (grammarDrv) version;
-
+  # Map nix style `0-unstable-YYYY-MM-DD` version identifiers to a PEP 440
+  # compatible form (`0+unstableYYYYMMDD`).
+  version = lib.pipe grammarDrv [
+    lib.getVersion
+    (lib.splitString "-")
+    (
+      parts:
+      let
+        version = lib.head parts;
+        metadata = lib.join "" (lib.tail parts);
+      in
+      if (metadata == "") then version else "${version}+${metadata}"
+    )
+  ];
   snakeCaseName = lib.replaceStrings [ "-" ] [ "_" ] name;
   drvPrefix = "python-${name}";
   # If the name of the grammar attribute differs from the grammar's symbol name,