Alluvial plots use variable-width ribbons and stacked bar plots to represent multi-dimensional or repeated-measures data with categorical or ordinal variables; see Riehmann, Hanfler, and Froehlich (2005) and Rosvall and Bergstrom (2010) . Alluvial plots are statistical graphics in the sense of Wilkinson (2006) ; they share elements with Sankey diagrams and parallel sets plots but are uniquely determined from the data and a small set of parameters. This package extends Wickham's (2010) layered grammar of graphics to generate alluvial plots from tidy data.