diff --git a/fluent.runtime/setup.py b/fluent.runtime/setup.py
index 326dcc01..7acc0802 100755
--- a/fluent.runtime/setup.py
+++ b/fluent.runtime/setup.py
@@ -26,7 +26,7 @@
       ],
       packages=['fluent', 'fluent.runtime'],
       install_requires=[
-          'fluent.syntax>=0.10',
+          'fluent.syntax>=0.10,<=0.11',
           'attrs',
           'babel',
           'pytz',
diff --git a/fluent.runtime/tox.ini b/fluent.runtime/tox.ini
index e566ee16..c32eb4d2 100644
--- a/fluent.runtime/tox.ini
+++ b/fluent.runtime/tox.ini
@@ -6,7 +6,7 @@ skipsdist=True
 setenv =
     PYTHONPATH = {toxinidir}
 deps =
-     fluent>=0.10
+     fluent.syntax>=0.10,<=0.11
      six
      attrs
      Babel