diff --git a/R/model.R b/R/model.R
index f9b8241c..f2c133cc 100644
--- a/R/model.R
+++ b/R/model.R
@@ -302,7 +302,16 @@ CmdStanModel <- R6::R6Class(
       if (length(private$stan_code_) == 0) {
         stop("'$print()' cannot be used because the 'CmdStanModel' was not created with a Stan file.", call. = FALSE)
       }
-      cat(self$code(), sep = "\n")
+      lines <- self$code()
+      line_num_indent <- nchar(as.character(length(lines)))
+      line_nums <- vapply(seq_along(lines), function(y) {
+        paste0(
+          rep(" ", line_num_indent - nchar(as.character(y))), y, collapse = ""
+        )
+      }, character(1))
+      cat(
+        paste(paste(line_nums, lines, sep = ": "), collapse = "\n"), sep = "\n"
+      )
       invisible(self)
     },
     stan_file = function() {