Rotterdamse Elektrische Tram (RET; ) is the main public transport operator in Rotterdam, Netherlands. It started in 1905 when they took over the city tram lines from RTM (Rotterdamsche Tramweg Maatschappij). It currently operates 64 bus lines, 11 tram lines and five metro/light rail lines in Rotterdam and the surrounding municipalities.
RET used to employ the national tariff system, like other local transport companies in the Netherlands. On 29 January 2009, fares on the metro switched to using an OV-chipkaart; bus and tram fares followed on 11 February 2010.