diff --git a/src/crate/theme/rtd/conf/__init__.py b/src/crate/theme/rtd/conf/__init__.py
index e7e739b3..f5a43171 100644
--- a/src/crate/theme/rtd/conf/__init__.py
+++ b/src/crate/theme/rtd/conf/__init__.py
@@ -19,6 +19,7 @@
 # with Crate these terms will supersede the license and you may use the
 # software solely pursuant to the terms of the relevant commercial agreement.
 import os
+import warnings
 
 from crate.theme import rtd as theme
 from crate.theme.rtd import __version__
@@ -183,6 +184,14 @@
 linkcheck_retries = 3
 linkcheck_timeout = 15
 
+# Suppress myst-nb deprecation warnings until fixed upstream.
+# https://github.com/executablebooks/MyST-NB/issues/645
+warnings.filterwarnings(
+    "ignore",
+    message=r".*myst_nb\.sphinx_\.Parser\.env.*",
+    category=DeprecationWarning,
+)
+
 # -- Options for MyST -------------------------------------------------
 myst_heading_anchors = 3
 myst_enable_extensions = [