diff --git a/R/rmarkdown/knit.R b/R/rmarkdown/knit.R
index 895fa27b5..734bd91a7 100644
--- a/R/rmarkdown/knit.R
+++ b/R/rmarkdown/knit.R
@@ -1,5 +1,5 @@
 # requires rmarkdown package to run (and knitr)
-if (!requireNamespace(rmarkdown, quietly = TRUE)) {
+if (!requireNamespace("rmarkdown", quietly = TRUE)) {
     stop("Knitting requires the {rmarkdown} package.")
 }
 
diff --git a/R/rmarkdown/preview.R b/R/rmarkdown/preview.R
index ecf5e6cc4..e77a0f5d5 100644
--- a/R/rmarkdown/preview.R
+++ b/R/rmarkdown/preview.R
@@ -1,5 +1,5 @@
 # requires rmarkdown package to run (and knitr)
-if (!requireNamespace(rmarkdown, quietly = TRUE)) {
+if (!requireNamespace("rmarkdown", quietly = TRUE)) {
     stop("Previewing documents requires the {rmarkdown} package.")
 }