diff --git a/DESCRIPTION b/DESCRIPTION
index bb05c99..cbc39c5 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -18,7 +18,6 @@ Depends:
 Imports:
     ggplot2 (>= 3.0.0),
     grid (>= 3.0.0),
-    plyr (>= 1.8.0),
     scales (>= 0.4.1),
     withr (>= 2.1.1)
 License: GPL-2 | file LICENSE
diff --git a/NAMESPACE b/NAMESPACE
index f5b2c4b..168a5c6 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -70,6 +70,5 @@ importFrom(ggplot2,ggproto)
 importFrom(ggplot2,layer)
 importFrom(grid,gList)
 importFrom(grid,gTree)
-importFrom(plyr,summarise)
 importFrom(scales,train_discrete)
 importFrom(stats,quantile)
diff --git a/R/geoms-gradient.R b/R/geoms-gradient.R
index 732fec3..9ff5383 100644
--- a/R/geoms-gradient.R
+++ b/R/geoms-gradient.R
@@ -239,7 +239,11 @@ GeomRidgelineGradient <- ggproto("GeomRidgelineGradient", Geom,
     data <- data[!missing_pos,]
 
     # munching for line
-    positions <- plyr::summarise(data, x = x, y = ymax, id = ids)
+    positions <- with(data, data.frame(
+      x = x,
+      y = ymax,
+      id = ids
+    ))
     munched_line <- ggplot2::coord_munch(coord, positions, panel_params)
 
     # We now break down the polygons further by fill color, since
@@ -267,8 +271,11 @@ GeomRidgelineGradient <- ggproto("GeomRidgelineGradient", Geom,
     }
 
     # munching for polygon
-    positions <- plyr::summarise(data,
-                                 x = c(x, rev(x)), y = c(ymax, rev(ymin)), id = c(ids, rev(ids)))
+    positions <- with(data, data.frame(
+      x = c(x, rev(x)),
+      y = c(ymax, rev(ymin)),
+      id = c(ids, rev(ids))
+    ))
     munched_poly <- ggplot2::coord_munch(coord, positions, panel_params)
 
     # calculate line and area grobs
diff --git a/R/geoms.R b/R/geoms.R
index 23a5aff..d930a28 100644
--- a/R/geoms.R
+++ b/R/geoms.R
@@ -97,7 +97,6 @@ geom_ridgeline <- function(mapping = NULL, data = NULL, stat = "identity",
 #' @format NULL
 #' @usage NULL
 #' @importFrom ggplot2 ggproto Geom
-#' @importFrom plyr summarise
 #' @export
 GeomRidgeline <- ggproto("GeomRidgeline", Geom,
   default_aes = aes(
@@ -258,12 +257,19 @@ GeomRidgeline <- ggproto("GeomRidgeline", Geom,
     ids[missing_pos] <- NA
 
     # munching for polygon
-    positions <- plyr::summarise(data,
-                                 x = c(x, rev(x)), y = c(ymax, rev(ymin)), id = c(ids, rev(ids)))
+    positions <- with(data, data.frame(
+      x = c(x, rev(x)),
+      y = c(ymax, rev(ymin)),
+      id = c(ids, rev(ids))
+    ))
     munched_poly <- ggplot2::coord_munch(coord, positions, panel_params)
 
     # munching for line
-    positions <- plyr::summarise(data, x = x, y = ymax, id = ids)
+    positions <- with(data, data.frame(
+      x = x,
+      y = ymax,
+      id = ids
+    ))
     munched_line <- ggplot2::coord_munch(coord, positions, panel_params)
 
     # calculate line and area grobs
diff --git a/R/geomsv.R b/R/geomsv.R
index 9ea1650..348d45a 100644
--- a/R/geomsv.R
+++ b/R/geomsv.R
@@ -93,7 +93,6 @@ geom_vridgeline <- function(mapping = NULL, data = NULL, stat = "identity",
 #' @format NULL
 #' @usage NULL
 #' @importFrom ggplot2 ggproto Geom draw_key_polygon
-#' @importFrom plyr summarise
 #' @export
 GeomVRidgeline <- ggproto("GeomVRidgeline", Geom,
   default_aes = aes(color = "black", fill = "grey80", x = 0, size = 0.5, linetype = 1,
@@ -173,12 +172,19 @@ GeomVRidgeline <- ggproto("GeomVRidgeline", Geom,
     ids[missing_pos] <- NA
 
     # munching for polygon
-    positions <- plyr::summarise(data,
-                                 y = c(y, rev(y)), x = c(xmax, rev(xmin)), id = c(ids, rev(ids)))
+    positions <- with(data, data.frame(
+      y = c(y, rev(y)),
+      x = c(xmax, rev(xmin)),
+      id = c(ids, rev(ids))
+    ))
     munched_poly <- ggplot2::coord_munch(coord, positions, panel_params)
 
     # munching for line
-    positions <- plyr::summarise(data, y = y, x = xmax, id = ids)
+    positions <- with(data, data.frame(
+      y = y,
+      x = xmax,
+      id = ids
+    ))
     munched_line <- ggplot2::coord_munch(coord, positions, panel_params)
 
     # placing the actual grob generation into a separate function allows us to override for geom_density_ridges2