This application provides a phase shifter and a remote electrical tilt antenna. The phase shifter includes a metal stripline, a first dielectric plate and a second dielectric plate. The metal stripline is clamped between the first dielectric plate and the second dielectric plate. At least one limiting protrusion protrudes along a length direction on a surface of the first dielectric plate and/or the second dielectric plate facing the metal stripline. The at least one limiting protrusion is configured to limit displacement of the first dielectric plate and the second dielectric plate relative to the metal stripline when the first dielectric plate and the second dielectric plate slide. The phase shifter provided in this application enables the first dielectric plate and/or the second dielectric plate to slide exactly along the length direction of the metal stripline without deviation, thereby realizing accurate control of a phase change by the phase shifter.