The quantized anomalous Hall (QAH) effect in magnetic topological insulators is studied through first-principles calculations. The tetradymite semiconductors Bi₂Te₃, Bi₂Se₃, and Sb₂Te₃, when doped with transition metals like Cr or Fe, form magnetically ordered insulators. These materials exhibit a topologically non-trivial electronic structure with a finite Chern number, leading to a quantized Hall conductance of e²/h without an external magnetic field. Unlike conventional dilute magnetic semiconductors, the magnetic order in these materials arises naturally from the host's large spin susceptibility, without requiring free carriers. The QAH effect is realized through a band inversion transition, which is facilitated by strong spin-orbit coupling. The magnetic dopants, such as Cr and Fe, lead to a ferromagnetic order with a high Curie temperature (up to 70K). The electronic structure of Bi₂Se₃ doped with transition metals shows that Cr and Fe doping results in an insulating magnetic state, while Ti and V doping lead to metallic states. The QAH effect is confirmed through calculations showing a quantized Hall conductance of e²/h, with the effect being robust at room temperature. The study highlights the potential of these materials for dissipationless charge transport in future electronic devices.The quantized anomalous Hall (QAH) effect in magnetic topological insulators is studied through first-principles calculations. The tetradymite semiconductors Bi₂Te₃, Bi₂Se₃, and Sb₂Te₃, when doped with transition metals like Cr or Fe, form magnetically ordered insulators. These materials exhibit a topologically non-trivial electronic structure with a finite Chern number, leading to a quantized Hall conductance of e²/h without an external magnetic field. Unlike conventional dilute magnetic semiconductors, the magnetic order in these materials arises naturally from the host's large spin susceptibility, without requiring free carriers. The QAH effect is realized through a band inversion transition, which is facilitated by strong spin-orbit coupling. The magnetic dopants, such as Cr and Fe, lead to a ferromagnetic order with a high Curie temperature (up to 70K). The electronic structure of Bi₂Se₃ doped with transition metals shows that Cr and Fe doping results in an insulating magnetic state, while Ti and V doping lead to metallic states. The QAH effect is confirmed through calculations showing a quantized Hall conductance of e²/h, with the effect being robust at room temperature. The study highlights the potential of these materials for dissipationless charge transport in future electronic devices.