# Installing SML/NJ under Windows

version 110.99.9, November 4, 2025

## Introduction

These instructions are for installing Standard ML of New Jersey (SML/NJ) as an application on Microsoft Windows. To use SML/NJ under the cygwin environment, see the installation instructions.

## Using the installer package

We provide a Microsoft Installer package for SML/NJ (https://smlnj.org/dist/working/110.99.9/smlnj-110.99.9.msi). The installer contains a full installation including nearly all of the optional components (it does not include "asdl", "mlrisc-tools", or "nowhere").

You can choose the installation directory. The default is `C:\Program Files\SMLNJ`. The `bin` directory containing the `sml` command is added to the default `PATH`, although you will need to re-open a command window to see the binding. The `SMLNJ_HOME` environment variable is also set to point at the location where SML/NJ was installed.

## Using SML/NJ on Windows

Once you have SML/NJ installed, you can launch the interactive top-level loop by selecting the application in the Start Menu. Alternatively, you can open a shell window and running the sml command.

## Building from sources

To build SML/NJ from the runtime sources and precompiled "bin" files requires a Unix shell (we use Cygwin) to fetch and unbundle the files. In addition, you will need to have a version of Microsoft’s Visual Studio available.

To build the Windows installation, use the following steps. We have marked those steps that must be done in a Unix shell with a "[UNIX]" prefix and those that must be done in the Visual Studio shell with "[VS]".

1. Create an installation directory for SML/NJ.

2. [UNIX] Use curl or wget to download the config.tgz file.

       % curl -O {dist-dir}/config.tgz

3. [UNIX] Unbundle the `config.tgz` file.

       % tar -xzf config.tgz

4. [UNIX] Run the `prepare-win-install.sh` script to download and unbundle the necessary source files. This script those files used in the standard installation on Windows.

       % config/prepare-win-install.sh

5. [VS] Run the SML/NJ installation script for Windows

       config\install.bat