diff --git a/src/libfetchers/github.cc b/src/libfetchers/github.cc
index 80598e7f836..f9eeef331fb 100644
--- a/src/libfetchers/github.cc
+++ b/src/libfetchers/github.cc
@@ -11,6 +11,7 @@
 #include <optional>
 #include <nlohmann/json.hpp>
 #include <fstream>
+#include <regex>
 
 namespace nix::fetchers {
 
@@ -332,9 +333,10 @@ struct GitLabInputScheme : GitArchiveInputScheme
     Hash getRevFromRef(nix::ref<Store> store, const Input & input) const override
     {
         auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
+        auto repo = std::regex_replace(getStrAttr(input.attrs, "repo"), std::regex("/"), "%2F");
         // See rate limiting note below
         auto url = fmt("https://%s/api/v4/projects/%s%%2F%s/repository/commits?ref_name=%s",
-            host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"), *input.getRef());
+            host, getStrAttr(input.attrs, "owner"), repo, *input.getRef());
 
         Headers headers = makeHeadersWithAuthTokens(host);
 
@@ -355,8 +357,9 @@ struct GitLabInputScheme : GitArchiveInputScheme
         // is 10 reqs/sec/ip-addr.  See
         // https://docs.gitlab.com/ee/user/gitlab_com/index.html#gitlabcom-specific-rate-limits
         auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
+        auto repo = std::regex_replace(getStrAttr(input.attrs, "repo"), std::regex("/"), "%2F");
         auto url = fmt("https://%s/api/v4/projects/%s%%2F%s/repository/archive.tar.gz?sha=%s",
-            host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"),
+            host, getStrAttr(input.attrs, "owner"), repo,
             input.getRev()->to_string(Base16, false));
 
         Headers headers = makeHeadersWithAuthTokens(host);
@@ -366,9 +369,10 @@ struct GitLabInputScheme : GitArchiveInputScheme
     void clone(const Input & input, const Path & destDir) const override
     {
         auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
+        auto repo = std::regex_replace(getStrAttr(input.attrs, "repo"), std::regex("/"), "%2F");
         // FIXME: get username somewhere
         Input::fromURL(fmt("git+https://%s/%s/%s.git",
-                host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo")))
+                host, getStrAttr(input.attrs, "owner"), repo))
             .applyOverrides(input.getRef(), input.getRev())
             .clone(destDir);
     }
diff --git a/src/nix/flake.md b/src/nix/flake.md
index 92f477917fd..d9d63bee0dc 100644
--- a/src/nix/flake.md
+++ b/src/nix/flake.md
@@ -277,6 +277,15 @@ Currently the `type` attribute can be one of the following:
 
   * `gitlab:veloren%2Fdev/rfcs`
 
+  However, if using Attribute set representation slashes are permitted as the ``repo`` value:
+  ```nix
+  inputs.nixpkgs = {
+    type  = "gitlab";
+    owner = "gitlab-org";
+    repo  = "release/tasks";
+  };
+  ```
+
 * `sourcehut`: Similar to `github`, is a more efficient way to fetch
   SourceHut repositories. The following attributes are required: