diff --git a/pkgs/development/compilers/open-watcom/bin.nix b/pkgs/development/compilers/open-watcom/bin.nix
index 1f8079908999..5e7805a31b30 100644
--- a/pkgs/development/compilers/open-watcom/bin.nix
+++ b/pkgs/development/compilers/open-watcom/bin.nix
@@ -1,4 +1,4 @@
-{ lib, stdenvNoCC, fetchurl, qemu, expect, writeScript, writeScriptBin, ncurses, bash, coreutils }:
+{ lib, stdenvNoCC, fetchurl, qemu, writeScript, writeScriptBin, ncurses, bash, coreutils, unixtools }:
 
 let
 
@@ -48,41 +48,6 @@ let
     exec ${wrapLegacyBinary} "$TARGET-unwrapped" "$TARGET"
   '';
 
-  # Do a scripted installation of OpenWatcom with its original installer.
-  #
-  # If maintaining this expect script turns out to be too much of a
-  # hassle, we can switch to just using `unzip' on the installer and
-  # the correct file permissions manually.
-  performInstall = writeScriptBin "performInstall" ''
-    #!${expect}/bin/expect -f
-
-    spawn [lindex $argv 0]
-
-    # Wait for button saying "I agree" with escape sequences.
-    expect "gree"
-
-    # Navigate to "I Agree!" and hit enter.
-    send "\t\t\n"
-
-    expect "Install Open Watcom"
-
-    # Where do we want to install to.
-    send "$env(out)\n"
-
-    expect "will be installed"
-
-    # Select Full Installation, Next
-    send "fn"
-
-    expect "Setup will now copy"
-
-    # Next
-    send "n"
-
-    expect "completed successfully"
-    send "\n"
-  '';
-
 in
 stdenvNoCC.mkDerivation rec {
   pname = "${passthru.prettyName}-unwrapped";
@@ -93,7 +58,7 @@ stdenvNoCC.mkDerivation rec {
     sha256 = "1wzkvc6ija0cjj5mcyjng5b7hnnc5axidz030c0jh05pgvi4nj7p";
   };
 
-  nativeBuildInputs = [ wrapInPlace performInstall ];
+  nativeBuildInputs = [ wrapInPlace unixtools.script ];
 
   dontUnpack = true;
   dontConfigure = true;
@@ -104,7 +69,9 @@ stdenvNoCC.mkDerivation rec {
   '';
 
   installPhase = ''
-    performInstall ./install-bin-unwrapped
+    # Command line options to do an unattended install are documented in
+    # https://github.com/open-watcom/open-watcom-v2/blob/master/bld/setupgui/setup.txt
+    script -c "./install-bin-unwrapped -dDstDir=$out -dFullInstall=1 -i"
 
     for e in $(find $out/binl -type f -executable); do
       echo "Wrapping $e"