Master–slave or master/slave may refer to:
- Master/slave (technology), a model of communication between two devices in computing
- Master–slave dialectic, a concept in Hegelian philosophy
- Master–slave morality, a central theme of Friedrich Nietzsche's works
- Master/slave (BDSM), a type of consensual relationship of dominance and submission
- Letter 47 (Seneca), also known as On Master and Slave
- "Master/Slave", a hidden track by the alternative rock band Pearl Jam on the album Ten
- Master Slave Husband Wife (2023), a history of Ellen and William Craft's escape from slavery by Ilyon Woo