A spinning reel includes a reel unit, a rotation transmission mechanism, a handle assembly, a rotor, a spool shaft, an oscillating mechanism, and a spool. The reel unit includes a reel body that has a first opening, and a first lid member that covers the first opening. The rotation transmission mechanism includes a master gear shaft that is rotatably mounted to the reel unit, and a master gear that is disposed on the master gear shaft integrally rotatably about a first shaft axis X. The reel body includes a first rotation support portion that rotatably supports the master gear shaft on a master gear side of the spool shaft. The first lid member includes a second rotation support portion that rotatably supports the master gear shaft on a first lid member side of the master gear.