diff --git a/.changes/unreleased/Under the Hood-20240221-104518.yaml b/.changes/unreleased/Under the Hood-20240221-104518.yaml
new file mode 100644
index 00000000000..56c077fcd1c
--- /dev/null
+++ b/.changes/unreleased/Under the Hood-20240221-104518.yaml	
@@ -0,0 +1,6 @@
+kind: Under the Hood
+body: Restrict protobuf to major version 4.
+time: 2024-02-21T10:45:18.315195-05:00
+custom:
+  Author: peterallenwebb
+  Issue: "9566"
diff --git a/dev-requirements.txt b/dev-requirements.txt
index 70e5bb41c1d..369d2665d13 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -9,7 +9,7 @@ ipdb
 mypy==0.981
 pip-tools
 pre-commit
-protobuf>=4.0.0
+protobuf>=4.0.0,<5.0.0
 pytest~=7.4
 pytest-cov
 pytest-csv~=3.0