diff --git a/requirements.txt b/requirements.txt
index 4440d00a0cd4d1e255f074b57fb1821c9677fb5d..fa149ecb69888fe150651f1ad05bc3b97b8763ed 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 docopt
+llvmlite==0.31
 numba
 awkward1>=0.2.13
 uproot>=3.11.1