diff --git a/R/build-quarto-articles.R b/R/build-quarto-articles.R
index 806297641..5df7ab63d 100644
--- a/R/build-quarto-articles.R
+++ b/R/build-quarto-articles.R
@@ -1,5 +1,12 @@
 build_quarto_articles <- function(pkg = ".", article = NULL, quiet = TRUE) {
   pkg <- as_pkgdown(pkg)
+  if (pkg$bs_version < 5) {
+    cli::cli_abort(c(
+      "Quarto articles require Bootstrap 5.",
+      "i" = "See details at {.url pkgdown.r-lib.org/articles/customise.html#getting-started}"),
+      call = NULL
+    )
+  }
 
   qmds <- pkg$vignettes[pkg$vignettes$type == "qmd", ]
   if (!is.null(article)) {