A hearing aid, in particular a BTE hearing aid, includes an ear insert having an earpiece and an attachment part being linked to a receiver. The earpiece includes an elongate adapter and a plurality of shields. The adapter is mounted on the attachment part and extends in a longitudinal direction. The earpiece is in a modular form and the at least one shield is exchangeably fitted onto the adapter. The adapter has a head with a rear abutment contour against which at least one of the shields abuts. In this way, the earpiece is particularly variably and flexibly configurable. A corresponding earpiece is also provided.