diff --git a/changelog.d/362.bugfix b/changelog.d/362.bugfix
new file mode 100644
index 00000000..a3d3a394
--- /dev/null
+++ b/changelog.d/362.bugfix
@@ -0,0 +1 @@
+Fix a bug causing Sygnal to fail when processing notifications without a `content` dict, when those notifications were destined for GCM. Contributed by @c-cal.
diff --git a/sygnal/gcmpushkin.py b/sygnal/gcmpushkin.py
index 1177c0aa..621c2fd7 100644
--- a/sygnal/gcmpushkin.py
+++ b/sygnal/gcmpushkin.py
@@ -669,7 +669,7 @@ def _build_data(
                     data[attr] = data[attr][0:MAX_BYTES_PER_FIELD]
 
         if api_version is APIVersion.V1:
-            if "content" in data:
+            if isinstance(data.get("content"), dict):
                 for attr, value in data["content"].items():
                     if not isinstance(value, str):
                         continue