diff --git a/Makefile b/Makefile
index 7d87057..4228496 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,8 @@
 FEATURES := nightly simd_backend
 
 doc:
-	cargo rustdoc --features "$(FEATURES)" -- --html-in-header docs/assets/rustdoc-include-katex-header.html
+	cargo +nightly rustdoc --features "$(FEATURES)" -- --html-in-header docs/assets/rustdoc-include-katex-header.html
 
 doc-internal:
-	cargo rustdoc --features "$(FEATURES)" -- --html-in-header docs/assets/rustdoc-include-katex-header.html --document-private-items
+	cargo +nightly rustdoc --features "$(FEATURES)" -- --html-in-header docs/assets/rustdoc-include-katex-header.html --document-private-items