diff --git a/flake.lock b/flake.lock
index 8a48e6ba..7b3d832a 100644
--- a/flake.lock
+++ b/flake.lock
@@ -35,6 +35,21 @@
         "type": "github"
       }
     },
+    "emacs-overlay": {
+      "locked": {
+        "lastModified": 1641032585,
+        "narHash": "sha256-2AQsgDZ4BdMzFCDtYllxDeVjdilmaQCi6nXnQNPAcpk=",
+        "owner": "nix-community",
+        "repo": "emacs-overlay",
+        "rev": "e5dc491b4294109bbef89bae64be3d2bd7b30549",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "emacs-overlay",
+        "type": "github"
+      }
+    },
     "flake-compat": {
       "flake": false,
       "locked": {
@@ -209,6 +224,7 @@
       "inputs": {
         "agenix": "agenix",
         "devshell": "devshell",
+        "emacs-overlay": "emacs-overlay",
         "flake-utils": "flake-utils",
         "home-manager": "home-manager",
         "neovim-nightly-overlay": "neovim-nightly-overlay",
diff --git a/flake.nix b/flake.nix
index 8e5ef816..8fadf861 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,6 +19,8 @@
 
     # Overlays.
     neovim-nightly-overlay.url = "github:nix-community/neovim-nightly-overlay";
+    emacs-overlay.url = "github:nix-community/emacs-overlay";
+
     rust-overlay.url = "github:oxalica/rust-overlay";
     rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
   };
@@ -32,6 +34,9 @@
         # Neovim nightly!
         inputs.neovim-nightly-overlay.overlay
 
+        # Emacs unstable version!
+        inputs.emacs-overlay.overlay
+
         # Rust overlay for them ease of setting up Rust toolchains.
         inputs.rust-overlay.overlay
       ];