Bachelor of Philosophy (B.Phil.; occasionally B.Ph. or Ph.B.) is the title of an academic degree. The degree usually involves considerable research, either through a thesis or supervised research projects. Despite its name, it is in many universities – for example, the University of Oxford – a graduate degree.

The B.Phil.'s earliest form is as a University of Oxford graduate degree. Originally, Oxford named its pre-doctoral graduate degrees the Bachelor of Philosophy (B.Phil.) (a two-year degree, partly taught and partly by research) and the Bachelor of Letters (B.Litt.) (a two-year research degree). After complaints, especially from overseas students, that this naming convention often meant that graduate degrees were not being recognised as such, the University renamed them Master of Philosophy (M.Phil.) and Master of Letters (M.Litt.). However, the Philosophy Faculty (then a Sub-Faculty) argued that its B.Phil. degree had become so well-known and respected in the philosophical world that it would be confusing to change the name. In philosophy, therefore, the degree continues to be called the B.Phil. Those who pass the degree are given the choice of taking a B.Phil. or an M.Phil.; few if any choose the latter.^{[citation needed]} (Note that Oxford also offers a number of other graduate degrees labeled as baccalaureate degrees: the law faculty's BCL; the music faculty's B.Mus; and the theology faculty's B.D.)