diff --git a/taskcluster/comm_taskgraph/loader/reference.py b/taskcluster/comm_taskgraph/loader/reference.py
index dec78e2fd5..4b65d55a62 100644
--- a/taskcluster/comm_taskgraph/loader/reference.py
+++ b/taskcluster/comm_taskgraph/loader/reference.py
@@ -9,6 +9,7 @@ import logging
 
 from taskgraph.util.yaml import load_yaml
 from taskgraph.util.python_path import find_object
+from six import text_type
 
 logger = logging.getLogger(__name__)
 
@@ -18,7 +19,11 @@ def _get_aliases(kind, job):
 
     if kind == "toolchain":
         if job["run"].get("toolchain-alias"):
-            aliases.add(job["run"].get("toolchain-alias"))
+            aliaslist = job["run"].get("toolchain-alias")
+            if isinstance(aliaslist, text_type):
+                aliaslist = [aliaslist]
+            for alias in aliaslist:
+                aliases.add(alias)
 
     return aliases