Mucia Tertia was a Roman matrona who lived in the 1st century BC. She was the daughter of Quintus Mucius Scaevola, the pontifex maximus, consul in 95 BC. Her mother was a Licinia that divorced her father to marry Quintus Caecilius Metellus Nepos, in a scandal mentioned by several sources. Her name, Mucia Tertia, would suggest that she was a third daughter, according to the Roman naming convention for women, though it is believed that this was instead to differentiate her from her two aunts. Mucia had also two younger brothers from her mother's second marriage (see Caecilius Metellus family tree), and she was a cousin (soror) of Q. Metellus Celer, consul in 60 BC, and of Q. Metellus Nepos, consul in 57 BC.