R4 can refer to either a specific astromech droid model or one of several individual astromech droids.
- M5-BZ served as a member of D-Squad during the Clone Wars.
- R4 (Rebel Alliance)
- R4-D6
- R4-E1
- R4-F5
- R4-G77
- R4-G9 was the astromech assigned to Obi-Wan Kenobi following the destruction of his previous droid.
- R4-I9
- R4-M9
- R4-M1
- R4-P17, nicknamed , was an astromech droid assigned to Obi-Wan Kenobi during the Clone Wars.
- R4-P44
- R9-D9
- R4-D12
- M5-BZ was a member of D-Squad who was destroyed during the Clone Wars.
- R4-A22
- R4-B11
- R4-D1
- R4-D2
- R4-D6
- R4-E1
- R4-F5
- R4-G9 was the second astromech droid assigned to Obi-Wan Kenobi.
- R4-H5
- R4-I9
- R4-J1
- R4-J9
- R4-K5
- R4-M1
- R4-M17
- R4-M6
- R4-M9
- R4-P17, nicknamed , was the astromech droid assigned to Obi-Wan Kenobi during the Clone Wars.
- R4-P22 was the astromech droid attached to Anakin Skywalker'sstarfighter, Azure Angel.
- R4-P44
- R4-S2
- R4-T8
- R9-D9