diff --git a/NEWS.md b/NEWS.md
index 633a46172b..e9b8ad523e 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -45,6 +45,8 @@
   systems (@teunbrand, #4690).
 * `geom_tile()` computes default widths and heights per panel instead of
   per layer (@teunbrand, #5740).
+* The `fill` of the `panel.border` theme setting is ignored and forced to be
+  transparent (#5782).
 
 # ggplot2 3.5.1
 
diff --git a/R/coord-.R b/R/coord-.R
index dc7090c352..ced1257b42 100644
--- a/R/coord-.R
+++ b/R/coord-.R
@@ -65,7 +65,9 @@ Coord <- ggproto("Coord",
     labels
   },
 
-  render_fg = function(panel_params, theme) element_render(theme, "panel.border"),
+  render_fg = function(panel_params, theme) {
+    element_render(theme, "panel.border", fill = NA)
+  },
 
   render_bg = function(self, panel_params, theme) {
     cli::cli_abort("{.fn {snake_class(self)}} has not implemented a {.fn render_bg} method.")
diff --git a/R/coord-polar.R b/R/coord-polar.R
index 6c8b4813b4..e0712760fb 100644
--- a/R/coord-polar.R
+++ b/R/coord-polar.R
@@ -265,7 +265,7 @@ CoordPolar <- ggproto("CoordPolar", Coord,
 
   render_fg = function(self, panel_params, theme) {
     if (is.null(panel_params$theta.major)) {
-      return(element_render(theme, "panel.border"))
+      return(element_render(theme, "panel.border", fill = NA))
     }
     arc <- self$start + c(0, 2 * pi)
     dir <- self$direction
@@ -297,7 +297,7 @@ CoordPolar <- ggproto("CoordPolar", Coord,
         unit(0.45 * cos(theta) + 0.5, "native"),
         hjust = 0.5, vjust = 0.5
       ),
-      element_render(theme, "panel.border")
+      element_render(theme, "panel.border", fill = NA)
     )
   },
 
diff --git a/R/coord-radial.R b/R/coord-radial.R
index 89c84dd5dc..b5ad621beb 100644
--- a/R/coord-radial.R
+++ b/R/coord-radial.R
@@ -357,11 +357,13 @@ CoordRadial <- ggproto("CoordRadial", Coord,
 
   render_fg = function(self, panel_params, theme) {
 
+    border <- element_render(theme, "panel.border", fill = NA)
+
     if (!self$r_axis_inside) {
       out <- grobTree(
         panel_guides_grob(panel_params$guides, "theta", theme),
         panel_guides_grob(panel_params$guides, "theta.sec", theme),
-        element_render(theme, "panel.border")
+        border
       )
       return(out)
     }
@@ -381,7 +383,7 @@ CoordRadial <- ggproto("CoordRadial", Coord,
       panel_guides_grob(panel_params$guides, "theta", theme),
       panel_guides_grob(panel_params$guides, "theta.sec", theme),
       left, right,
-      element_render(theme, "panel.border")
+      border
     )
   },
 
diff --git a/R/theme-defaults.R b/R/theme-defaults.R
index 2066679533..6ecd6d68c0 100644
--- a/R/theme-defaults.R
+++ b/R/theme-defaults.R
@@ -269,7 +269,7 @@ theme_bw <- function(base_size = 11, base_family = "",
     theme(
       # white background and dark border
       panel.background = element_rect(fill = "white", colour = NA),
-      panel.border     = element_rect(fill = NA, colour = "grey20"),
+      panel.border     = element_rect(colour = "grey20"),
       # make gridlines dark, same contrast with white as in theme_grey
       panel.grid = element_line(colour = "grey92"),
       panel.grid.minor = element_line(linewidth = rel(0.5)),
@@ -303,7 +303,7 @@ theme_linedraw <- function(base_size = 11, base_family = "",
       #     0.5 clipped looks like 0.25
 
       # pure black panel border and grid lines, but thinner
-      panel.border     = element_rect(fill = NA, colour = "black", linewidth = rel(1)),
+      panel.border     = element_rect(colour = "black", linewidth = rel(1)),
       panel.grid       = element_line(colour = "black"),
       panel.grid.major = element_line(linewidth = rel(0.1)),
       panel.grid.minor = element_line(linewidth = rel(0.05)),
@@ -337,7 +337,7 @@ theme_light <- function(base_size = 11, base_family = "",
     theme(
       # white panel with light grey border
       panel.background = element_rect(fill = "white", colour = NA),
-      panel.border     = element_rect(fill = NA, colour = "grey70", linewidth = rel(1)),
+      panel.border     = element_rect(colour = "grey70", linewidth = rel(1)),
       # light grey, thinner gridlines
       # => make them slightly darker to keep acceptable contrast
       panel.grid       = element_line(colour = "grey87"),
@@ -612,7 +612,7 @@ theme_test <- function(base_size = 11, base_family = "",
     legend.box.spacing = rel(2),
 
     panel.background =   element_rect(fill = "white", colour = NA),
-    panel.border =       element_rect(fill = NA, colour = "grey20"),
+    panel.border =       element_rect(colour = "grey20"),
     panel.grid.major =   element_blank(),
     panel.grid.minor =   element_blank(),
     panel.spacing =      NULL,
diff --git a/R/theme.R b/R/theme.R
index f03d2a67ef..f151a316a7 100644
--- a/R/theme.R
+++ b/R/theme.R
@@ -226,7 +226,7 @@
 #' # Panels --------------------------------------------------------------------
 #'
 #' p1 + theme(panel.background = element_rect(fill = "white", colour = "grey50"))
-#' p1 + theme(panel.border = element_rect(linetype = "dashed", fill = NA))
+#' p1 + theme(panel.border = element_rect(linetype = "dashed"))
 #' p1 + theme(panel.grid.major = element_line(colour = "black"))
 #' p1 + theme(
 #'   panel.grid.major.y = element_blank(),
diff --git a/man/theme.Rd b/man/theme.Rd
index 13a88a2e2a..5635049b5c 100644
--- a/man/theme.Rd
+++ b/man/theme.Rd
@@ -412,7 +412,7 @@ p1 + theme(plot.background = element_rect(fill = "green"))
 # Panels --------------------------------------------------------------------
 
 p1 + theme(panel.background = element_rect(fill = "white", colour = "grey50"))
-p1 + theme(panel.border = element_rect(linetype = "dashed", fill = NA))
+p1 + theme(panel.border = element_rect(linetype = "dashed"))
 p1 + theme(panel.grid.major = element_line(colour = "black"))
 p1 + theme(
   panel.grid.major.y = element_blank(),