diff --git a/third_party/lisp/cl-change-case.nix b/third_party/lisp/cl-change-case.nix
new file mode 100644
index 000000000..b66368a9b
--- /dev/null
+++ b/third_party/lisp/cl-change-case.nix
@@ -0,0 +1,22 @@
+{ depot, pkgs, ... }:
+
+let src = with pkgs; srcOnly lispPackages.cl-change-case;
+in depot.nix.buildLisp.library {
+  name = "cl-change-case";
+
+  deps = with depot.third_party.lisp; [ cl-ppcre cl-ppcre.unicode ];
+
+  srcs = [ (src + "/src/cl-change-case.lisp") ];
+
+  tests = {
+    name = "cl-change-case-tests";
+    srcs = [ (src + "/t/cl-change-case.lisp") ];
+    deps = [
+      depot.third_party.lisp.fiveam
+    ];
+
+    expression = ''
+      (5am:run! :cl-change-case)
+    '';
+  };
+}
diff --git a/third_party/lisp/cl-ppcre.nix b/third_party/lisp/cl-ppcre.nix
index 561e30619..7cb99db63 100644
--- a/third_party/lisp/cl-ppcre.nix
+++ b/third_party/lisp/cl-ppcre.nix
@@ -24,4 +24,16 @@ in depot.nix.buildLisp.library {
     "scanner.lisp"
     "api.lisp"
   ];
+
+  passthru = {
+    unicode = depot.nix.buildLisp.library {
+      name = "cl-ppcre-unicode";
+      deps = with depot.third_party.lisp; [ cl-ppcre cl-unicode ];
+
+      srcs = map (f: src + ("/cl-ppcre-unicode/" + f)) [
+        "packages.lisp"
+        "resolver.lisp"
+      ];
+    };
+  };
 }
diff --git a/third_party/lisp/str.nix b/third_party/lisp/str.nix
new file mode 100644
index 000000000..556f9cc30
--- /dev/null
+++ b/third_party/lisp/str.nix
@@ -0,0 +1,49 @@
+{ depot, pkgs, ... }:
+
+let
+  inherit (depot.nix) buildLisp;
+  src = with pkgs; srcOnly lispPackages.str;
+in
+buildLisp.library {
+  name = "str";
+
+  deps = with depot.third_party.lisp; [
+    {
+      sbcl = buildLisp.bundled "uiop";
+      default = buildLisp.bundled "asdf";
+    }
+    cl-ppcre
+    cl-ppcre.unicode
+    cl-change-case
+  ];
+
+  srcs = [
+    (pkgs.runCommand "str.lisp" { } ''
+      substitute ${src}/str.lisp $out \
+        --replace-fail \
+          '(asdf:component-version (asdf:find-system "str"))' \
+          '"${pkgs.lispPackages.str.meta.version}"'
+    '')
+  ];
+
+  brokenOn = [
+    "ccl" # In REPLACE-USING: Shouldn't assign to variable I
+  ];
+
+  tests = {
+    name = "str-test";
+    srcs = [ (src + "/test/test-str.lisp") ];
+    deps = [
+      {
+        sbcl = depot.nix.buildLisp.bundled "uiop";
+        default = depot.nix.buildLisp.bundled "asdf";
+      }
+      depot.third_party.lisp.prove
+      depot.third_party.lisp.fiveam
+    ];
+
+    expression = ''
+      (fiveam:run! 'str::test-str)
+    '';
+  };
+}