The manus of terrestrial tetrapods is involved in various environmental interactions, including locomotion, food acquisition and many more, meaning that complex selective pressures have acted upon its morphology. Non-avian dinosaurs are an excellent group to study manus shape evolution given their wide range of body sizes, stances, and ecological niches. Their ancestral bipedal bauplan allowed diverse morphologies to evolve, but multiple independent reversions to quadrupedality likely imposed convergent mechanical constraints on manus form. I present a study on metacarpus shape evolution in non-avian dinosaurs using 2D geometric morphometrics. Photographs and published images of the five metacarpals (pentadactyl ancestral state) in dorsal view were obtained for 87 taxa, representing all major clades. Shape variation of each element was quantified using four landmarks and four curves of 50 semilandmarks. Phylogenetically-informed Principal Component Analysis (PCA) and MANOVA, analyses of disparity and evolutionary rates were conducted using the R packages geomorph, phytools and mvMORPH. Morphological convergence was tested using RRphylo. Allometry had a significant effect (up to 17%), the first PCA axis explaining over 74% of shape variation, separating taxa with longer, slender metacarpals from those with proportionally shorter shafts and wider proximal/distal ends. Substantial differences between bipedal and quadrupedal taxa were not found, but results suggest two quadrupedal morphotypes: stout metacarpals in thyreophorans, ceratopsians, and some basal sauropodomorphs; longer, slender elements in sauropods and hadrosauroids. In sauropodomorph and ornithopod evolution there is a clear convergence toward a more ‘columnar’ manus structure.