diff --git a/NEWS.md b/NEWS.md
index 8893fdbd6d..606d2b7c92 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -205,6 +205,9 @@ up correct aspect ratio, and draws a graticule.
 * In all layers that use it, `linemitre` now defaults to 10 (instead of 1)
   to better match base R.
 
+* `geom_boxplot()` now supplies default value if no `x` aesthetic present
+  (@foo-bar-baz-qux, #2110).
+
 * `geom_density()` drops groups with fewer than two data points and throws a
   warning. For groups with two data points, the density values are now
   calculated with `stats::density` (@karawoo, #2127).
diff --git a/R/stat-boxplot.r b/R/stat-boxplot.r
index b29eefc34c..d444794afa 100644
--- a/R/stat-boxplot.r
+++ b/R/stat-boxplot.r
@@ -42,11 +42,15 @@ stat_boxplot <- function(mapping = NULL, data = NULL,
 #' @usage NULL
 #' @export
 StatBoxplot <- ggproto("StatBoxplot", Stat,
-  required_aes = c("x", "y"),
+  required_aes = c("y"),
   non_missing_aes = "weight",
+  setup_data = function(data, params) {
+    data$x <- data$x %||% 0
+    data
+  },
 
   setup_params = function(data, params) {
-    params$width <- params$width %||% (resolution(data$x) * 0.75)
+    params$width <- params$width %||% (resolution(data$x %||% 0) * 0.75)
 
     if (is.double(data$x) && !has_groups(data) && any(data$x != data$x[1L])) {
       warning(