Issue 21 of Star Wars: Build Your Own R2-D2, a De Agostini publication, is the twenty-first installment of the Star Wars: Build Your Own R2-D2 series. This issue included components for the right leg, along with fixing screws for the head frame, sensor, and leg, all intended for constructing the R2-D2 model. Furthermore, it featured articles titled "The Return of C-3PO," "8D8-series smelter droids," and "Nanorobotics."