Two-dimensional materials (2DMs) are crystals with one to a few layers of atoms and are being used in many fields such as optical modulator, photodetector, optical switch, and ultrafast lasers. Their exceptional opto-electronic and nonlinear optical properties make them as a suitable saturable absorber for laser cavities. This chapter focuses on the recent progress in ultrafast laser use 2DM as a saturable absorber (SA). 2DMs traditionally include graphene, topological insulators (TIs), transition metal dichalcogenides (TMDs), as well as new materials such as black phosphorus (BP), bismuthene, antimonene, and MXenes. Material characteristics, fabrication techniques, and nonlinear properties are also introduced. Finally, future perspectives of ultrafast lasers based on 2D materials are also addressed.