Reslosound Limited, also known as Reslo, were a manufacturer of electrical recording equipment, especially of RB Ribbon Microphones. They were producing microphones as early as 1953, but became more well known in the 1960s with their microphones being used at live music events, recording studios and by broadcasters, specifically the BBC. Their sales division was based in London and their manufacturing and service in Essex.

In 1963, the company joined Derritron, a group of electronics companies. Little more is known about Reslosound beyond the 1960s, but the Derritron group was liquidated in 1982.