A bacteriocyte (Greek for bacteria cell), also known as a mycetocyte, is a specialized adipocyte found primarily in certain insect groups such as aphids, tsetse flies, German cockroaches, weevils. These cells contain endosymbiotic organisms such as bacteria and fungi, which provide essential amino acids and other chemicals to their host. Bacteriocytes may aggregate into a specialized organ called the bacteriome.

Endosymbiosis with microorganisms is common in insects. More than 10% of insect species rely upon intracellular bacteria for their development and survival. Endosymbionts and their relationships with their hosts are diverse both functionally and genetically. However, the host cell in which bacterial and fungal endosymbionts reside is mostly unknown.