diff --git a/requirements.txt b/requirements.txt
index dd15a69ebf6dade1ca2fb2df0bdc3644b6b8c6d8..e6e46f9565cfcb86622ea9494ef4682b1f83edcd 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ git+https://github.com/inducer/modepy
 git+https://github.com/inducer/pyopencl
 git+https://github.com/inducer/islpy
 git+https://github.com/inducer/loopy
-git+https://gitlab.tiker.net/inducer/boxtree
+git+https://gitlab.tiker.net/inducer/boxtree@fast-m2l
 git+https://github.com/inducer/meshmode
 git+https://gitlab.tiker.net/inducer/sumpy
 git+https://gitlab.tiker.net/inducer/pyfmmlib