diff --git a/requirements.txt b/requirements.txt
index a2b360de74ed5068846780c3cf4591b652d3ce35..39255f351bfc49ade027f2840f0ab4376b35e0b6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
 attrs
 zope.interface
-twisted
+twisted[tls]
 https://github.com/tahoe-lafs/tahoe-lafs/archive/b35a8908f4096ccae35da78b0e7dde96d6cf1667.zip#egg=tahoe-lafs