diff --git a/pkgs/development/compilers/smlnj/bootstrap.nix b/pkgs/development/compilers/smlnj/bootstrap.nix
index 91eb9fc84172..aacebd48e9e3 100644
--- a/pkgs/development/compilers/smlnj/bootstrap.nix
+++ b/pkgs/development/compilers/smlnj/bootstrap.nix
@@ -1,3 +1,7 @@
+# This derivation should be redundant, now that regular smlnj works on Darwin,
+# and is preserved only for pre-existing direct usage. New use cases should
+# just use the regular smlnj derivation.
+
 { lib, stdenv, fetchurl, cpio, rsync, xar, makeWrapper }:
 
 stdenv.mkDerivation rec {
diff --git a/pkgs/development/compilers/smlnj/default.nix b/pkgs/development/compilers/smlnj/default.nix
index 3e987e8ccdaf..d6d50f0303f6 100644
--- a/pkgs/development/compilers/smlnj/default.nix
+++ b/pkgs/development/compilers/smlnj/default.nix
@@ -1,11 +1,9 @@
-{ lib, stdenv, fetchurl }:
+{ lib, stdenv, fetchurl, Libsystem }:
 let
   version = "110.95";
   baseurl = "http://smlnj.cs.uchicago.edu/dist/working/${version}";
 
-  isArch64 = stdenv.system == "x86_64-linux";
-
-  arch = if isArch64
+  arch = if stdenv.is64bit
     then "64"
     else "32";
 
@@ -14,7 +12,7 @@ let
   boot64 = { url = "${baseurl}/boot.amd64-unix.tgz";
              sha256 = "1zn96a83kb6bn6228yfjsvb58m2qxw9k4j3qz0p9c8za479w4ch6"; };
 
-  bootBinary = if isArch64
+  bootBinary = if stdenv.is64bit
                then boot64
                else boot32;
 
@@ -53,6 +51,10 @@ in stdenv.mkDerivation {
     sed -i '/PATH=/d' config/_arch-n-opsys base/runtime/config/gen-posix-names.sh
     echo SRCARCHIVEURL="file:/$TMP" > config/srcarchiveurl
     patch --verbose config/_heap2exec ${./heap2exec.diff}
+  '' + lib.optionalString stdenv.isDarwin ''
+    # Locate standard headers like <unistd.h>
+    substituteInPlace base/runtime/config/gen-posix-names.sh \
+      --replace "\$SDK_PATH/usr" "${Libsystem}"
   '';
 
   unpackPhase = ''
@@ -83,7 +85,7 @@ in stdenv.mkDerivation {
     description = "Standard ML of New Jersey, a compiler";
     homepage    = "http://smlnj.org";
     license     = licenses.bsd3;
-    platforms   = [ "x86_64-linux" "i686-linux" ];
+    platforms   = [ "x86_64-linux" "i686-linux" "x86_64-darwin" ];
     maintainers = with maintainers; [ thoughtpolice ];
   };
 }
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index a2952e8a7c89..5afb6fa3f613 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -12069,8 +12069,11 @@ in
 
   shmig = callPackage ../development/tools/database/shmig { };
 
+  # smlnjBootstrap should be redundant, now that smlnj works on Darwin natively
   smlnjBootstrap = callPackage ../development/compilers/smlnj/bootstrap.nix { };
-  smlnj = callPackage ../development/compilers/smlnj { };
+  smlnj = callPackage ../development/compilers/smlnj {
+    inherit (darwin) Libsystem;
+  };
 
   smlpkg = callPackage ../tools/package-management/smlpkg { };
 
@@ -30080,11 +30083,7 @@ in
 
   iprover = callPackage ../applications/science/logic/iprover { };
 
-  jonprl = callPackage ../applications/science/logic/jonprl {
-    smlnj = if stdenv.isDarwin
-      then smlnjBootstrap
-      else smlnj;
-  };
+  jonprl = callPackage ../applications/science/logic/jonprl { };
 
   key = callPackage ../applications/science/logic/key { };
 
@@ -30143,19 +30142,11 @@ in
 
   tptp = callPackage ../applications/science/logic/tptp {};
 
-  celf = callPackage ../applications/science/logic/celf {
-    smlnj = if stdenv.isDarwin
-      then smlnjBootstrap
-      else smlnj;
-  };
+  celf = callPackage ../applications/science/logic/celf { };
 
   fast-downward = callPackage ../applications/science/logic/fast-downward { };
 
-  twelf = callPackage ../applications/science/logic/twelf {
-    smlnj = if stdenv.isDarwin
-      then smlnjBootstrap
-      else smlnj;
-  };
+  twelf = callPackage ../applications/science/logic/twelf { };
 
   verifast = callPackage ../applications/science/logic/verifast {};