diff --git a/setup.py b/setup.py
index 744883c3f9..77876ff758 100644
--- a/setup.py
+++ b/setup.py
@@ -33,6 +33,7 @@
         "mdformat-gfm>=0.3.5",  # Needed for formatting GitHub-flavored markdown
         "mdformat-frontmatter>=0.4.1",  # Needed for frontmatters-style headers in issue templates
         "mdformat-pyproject>=0.0.1",  # Allows configuring in pyproject.toml
+        "pydantic<2.0",  # Needed for successful type check. TODO: Remove after full v2 support.
     ],
     "doc": [
         "myst-parser>=1.0.0,<2",  # Parse markdown docs