Reslo, trading as Reslosound, is a British microphone maker based in Romford, Essex, that produced audio equipment from around 1937 through 1978. The company is best known for its ribbon microphones, particularly the RV (late 1940s through mid-1950s) and the long-running RB and its variants, which remained in production until 1973. The RB became closely associated with British pop and broadcast culture: it was widely used at Liverpool's Cavern Club during the early 1960s, earning the nickname "the Beatles mic," and was a fixture in BBC studios and on programs such as Grandstand.

In the early 1970s the company introduced a line of dynamic microphones and its first electret condenser, alongside a refreshed logo, before the original operation wound down. The brand has since been revived as a small specialist outfit that refurbishes vintage Reslo ribbons — replacing ribbons and offering rebuilt examples of the RB, RV, and CR — and also assembles XLR microphone cables using Van Damme cable and Neutrik connectors. Reslo ribbons remain sought after by engineers and musicians for the warm, midrange-forward tone characteristic of mid-century British ribbon design.

Reslo has 2 products cataloged on Equipboard, including Ribbon Microphones. Their gear is featured by 3 artists, with the strongest followings in Rock and Pop. Notable users include Paul McCartney, John Lennon, and Mick Jagger.