diff --git a/R/libpaths.R b/R/libpaths.R
index 6743d0260..ff937364c 100644
--- a/R/libpaths.R
+++ b/R/libpaths.R
@@ -147,7 +147,7 @@ renv_libpaths_user <- function() {
   for (envvar in envvars) {
 
     value <- Sys.getenv(envvar, unset = NA)
-    if (is.na(value) || value == "<NA>" || !nzchar(value))
+    if (is.na(value) || value == "<NA>" || value == "NULL" || !nzchar(value))
       next
 
     parts <- strsplit(value, .Platform$path.sep, fixed = TRUE)[[1]]