diff --git a/NEWS.md b/NEWS.md
index 6dc83ab..ca6c877 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,7 +4,7 @@
   the `labs` argument (#13).
 * `ggtibble` and `gglist` objects now work with the ggplot2 `%+%` operator (#16)
 * A new `ggsave()` generic function will now enable simpler saving of `ggtibble`
-  and `gglist` objects.
+  and `gglist` objects (unique filenames are required to save).
 
 # ggtibble 1.0.1
 
diff --git a/R/ggsave.R b/R/ggsave.R
index e90aff2..7d9637d 100644
--- a/R/ggsave.R
+++ b/R/ggsave.R
@@ -19,7 +19,7 @@ ggsave <- function(filename,
 }
 
 #' @describeIn ggsave Save the figures in a `gglist` object
-#' @param filename A vector of file names for each `plot`
+#' @param filename A vector of unique file names for each `plot`
 #' @export
 ggsave.gglist <- function(filename,
                           plot,
@@ -34,7 +34,11 @@ ggsave.gglist <- function(filename,
                           bg = NULL,
                           create.dir = FALSE,
                           ...) {
-  stopifnot(length(filename) == length(plot))
+  if (length(filename) != length(plot)) {
+    stop("There must be one `filename` per `plot`")
+  } else if (any(duplicated(filename))) {
+    stop("Each `filename` must be unique")
+  }
   ret <-
     vapply(
       X = seq_along(plot),
diff --git a/tests/testthat/test-ggsave.R b/tests/testthat/test-ggsave.R
index 0088e0a..e290ff7 100644
--- a/tests/testthat/test-ggsave.R
+++ b/tests/testthat/test-ggsave.R
@@ -23,4 +23,17 @@ test_that("ggsave", {
     expected_files
   )
   unlink(expected_files)
+
+  # Enough filenames must be given
+  expect_error(
+    ggsave(filename = "a.png", plot = all_plots$figure, path = tempdir()),
+    regexp = "There must be one `filename` per `plot`",
+    fixed = TRUE
+  )
+  # Filenames must be unique (don't accidentally overwrite anything)
+  expect_error(
+    ggsave(filename = "{Bunit}.png", plot = all_plots, path = tempdir()),
+    regexp = "Each `filename` must be unique",
+    fixed = TRUE
+  )
 })