Using density functional theory and many-body perturbation theory, we systematically investigate the optoelectronic properties of AlSb monolayer, which has been recently synthesized by molecular beam epitaxy [ACS Nano 2021, 15, 5, 8184–8191]. After confirming the dynamical stability of the monolayer, we analyze its electronic properties at different levels of theory without (PBE, HSE03, HSE06) and with (G\documentclass[12pt]{minimal}
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				\begin{document}$$_0$$\end{document}0, and GW) electron-electron interaction. The results show that AlSb monolayer is a semiconductor with a direct quasiparticle band gap of 1.35 eV while its electronic structure is dominated by spin-orbit coupling. Also, we study the optical properties of the monolayer by solving the Bethe–Salpeter equation. In this regard, the effects of spin-orbit coupling, electron–electron correlation, and electron–hole interaction on the optical spectrum of the monolayer are evaluated. Based on the highest level of theory, the first bright exciton is found to be located at 0.97 eV, in excellent agreement with the experimental value (0.93 eV). Moreover, the exciton binding energy, effective mass, and Bohr radius are obtained 0.38 eV, 0.25 m\documentclass[12pt]{minimal}
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				\begin{document}$$_0$$\end{document}0, and 6.31 Å, respectively. This work provides a better understanding of the electronic, optical, and excitonic properties of AlSb monolayer and may shed light on its potential applications.