diff --git a/devshell.toml b/devshell.toml
index 8012e7d3..62b03d38 100644
--- a/devshell.toml
+++ b/devshell.toml
@@ -11,6 +11,11 @@ packages = [
   "mdsh",
 ]
 
+# Expose all the dependencies from a package to the environment.
+packagesFrom = [
+  "direnv"
+]
+
 # Message Of The Day (MOTD) is displayed when entering the environment with an
 # interactive shell. By default it will show the project name.
 #
diff --git a/mkDevShell/options.nix b/mkDevShell/options.nix
index c2537031..095c4ff2 100644
--- a/mkDevShell/options.nix
+++ b/mkDevShell/options.nix
@@ -116,6 +116,14 @@ let
       '';
     };
   };
+
+  # Returns a list of all the input derivation ... for a derivation.
+  inputsOf = drv:
+    (drv.buildInputs or [ ]) ++
+    (drv.nativeBuildInputs or [ ]) ++
+    (drv.propagatedBuildInputs or [ ]) ++
+    (drv.propagatedNativeBuildInputs or [ ])
+  ;
 in
 {
   options = {
@@ -215,6 +223,15 @@ in
       '';
     };
 
+    packagesFrom = mkOption {
+      type = types.listOf strOrPackage;
+      default = [ ];
+      description = ''
+        Add all the build dependencies from the listed packages to the
+        environment.
+      '';
+    };
+
   };
 
   config = {
@@ -230,8 +247,10 @@ in
     ];
 
     packages =
-      builtins.filter
-        (x: x != null)
-        (map (x: x.package) config.commands);
+      # Get all the packages from the commands
+      builtins.filter (x: x != null) (map (x: x.package) config.commands)
+      # Get all the packages from packagesFrom
+      ++ builtins.foldl' (sum: drv: sum ++ (inputsOf drv)) [ ] config.packagesFrom
+    ;
   };
 }