Strain engineering is a practical and effective method to tune the optical and electronic properties of materials and to enhance their physical characteristics. Recent studies found that it provides a significant enhancement in the transport properties of materials based on chalcogenides such as transition metal dichalcogenide (TMD) monolayers. We investigate the effect of biaxial strain on the electronic structure and transport properties of AlS and AlSe monolayers using first principles calculations in the framework of density functional theory and Boltzmann transport theory. The electronic band structure shows that AlS and AlSe monolayers are indirect bandgap semiconductors and the band gap varies under the application of biaxial strain. The strain changes the relative positions and number of conduction bands as well as valence band extrema from its equilibrium and therefore tunes the electronic transport coefficients. Our calculations show that the application of biaxial strain increases the Seebeck coefficient as well as electrical conductivity which further enhances the power factor of n-type and p-type AlX (X = S or Se) monolayers.