The yellow-bellied chat-tyrant (Silvicultrix diadema) is a species of passerine bird in the family Tyrannidae. It is 12–12.5 cm (4.7–4.9 in) in length. It is a chunky bird with a short, thin bill. It is mostly olive with an ochre yellow forehead and long yellow eyebrow. It has dusky colored wings and tail with two rufous tail bars. It is mostly found in Colombia, Ecuador, Peru, and Venezuela. It feeds in separated pairs hunting near the ground in foliage.