diff --git a/docs/guides/contribute.md b/docs/guides/contribute.md
index d1feac0..f964d0c 100644
--- a/docs/guides/contribute.md
+++ b/docs/guides/contribute.md
@@ -81,7 +81,7 @@ make SPHINXOPTS="OPTION VALUE" BUILDER
 The following example shows how to clean then build a live HTML preview of the documentation while suppressing syntax highlighting failures.
 
 ```shell
-make SPHINXOPTS="-D suppress_warnings=['misc.highlighting_failure']" clean livehtml
+make SPHINXOPTS="-D suppress_warnings='misc.highlighting_failure'" clean livehtml
 ```
 
 You can also pass options to vale in the `VALEOPTS` environment variable.
diff --git a/news/47.documentation b/news/47.documentation
new file mode 100644
index 0000000..0701353
--- /dev/null
+++ b/news/47.documentation
@@ -0,0 +1 @@
+Fix `suppress_warnings` syntax for `SPHINXOPTS`. @stevepiercy