SML/NJ Standard ML of New Jersey                          

Standard ML of New Jersey (abbreviated SML/NJ) is a compiler for the Standard ML '97 programming language with associated libraries, tools, and documentation. SML/NJ is free, open source software.

Support for 64-bit architectures

We have been working on porting SML/NJ to run on 64-bit architectures (specifically the amd64 or x86-64) since version 110.81. This project was a major undertaking because of significant technical debt in the compiler. As of September 2019, we can generate 64-bit machine code for the system and we are in the process of debugging the generated code. We hope to have a version suitable for beta testing later this month or, at the latest, in early October.


The latest release is 110.93; we believe that this version is stable, but there have been a lot of low-level changes that might have introduced bugs, so if you have any problems with the system you should report them and then revert to 110.87. Previous versions are also available through our release history page. A history of the changes to the system is also available.

Subversion access

Our master source repository is kept on a FusionForge server (a successor to GForge) under Subversion control. We provide anonymous read-only access to the repository, so anyone can download a snapshot of the most recent sources at any time. Instructions are here.

What's New

Downloading SML/NJ


Documentation and Literature

Reporting Bugs



This project is based upon work supported in part by the National Science Foundation under Grant No. CNS-0454136.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).

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