Cephaloleia diplothemium is a species of beetle of the family Chrysomelidae. It is found in Brazil (Bahia, Goiás, Matto Grosso, Minas Gerais).
Adults reach a length of about 3âÂÂ3.5 mm. The head and pronotum are black with a weak metallic sheen, while the elytron is metallic-green. The mouthparts and antennae are brownish and the legs and sides of the abdomen are pitch-brown.
The recorded host plant is Diplothemium caudescens.