Topological insulators (TIs) host robust edge or surface states protected by time-reversal symmetry (TRS), which makes them prime candidates for applications in spintronic devices. A promising avenue of research for the development of functional TI devices has involved doping of three-dimensional (3D) TI thin film and bulk materials with magnetic elements. This approach aims to break the TRS and open a surface band gap near the Dirac point. Utilizing this gapped surface state allows for a wide range of novel physical effects to be observed, paving a way for applications in spintronics and quantum computation. This review focuses on the research of 3D TIs doped with manganese (Mn). We summarize major progress in the study of Mn doped chalcogenide TIs, including Bi₂Se₃, Bi₂Te₃, and Bi₂(Te,Se)₃. The transport properties, in particular the anomalous Hall effect, of the Mn-doped Bi₂Se₃ are discussed in detail. Finally, we conclude with future prospects and challenges in further studies of Mn doped TIs.