Physical properties of Al-doped GaSe or GaSe:Al(0.01, 0.02, 0.05, 0.1, 0.5, 1, 2 wt%) crystals in charge composition were studied in comparison with pure GaSe to reveal the potentials for sub- and microwave elec-trooptical application. Aluminium was not detected in GaSe:Al by X-ray chemical analysis. It was found that resistivity of GaSe:Al drastically increases with Al doping up to 105-107 in comparison with (1-3)·102 in pure GaSe and 103 Om-cm in GaSe:S(2 wt%). No significant changes in optical properties to that in GaSe (α≤0.1-0.2 cm-1) were found at 0.01-0.02 wt% Al-doping but 2-fold to 3-fold increase in hardness at 0.5 wt% Al-doping. GaSe physical properties modified by Al-doping make it very attractive for mid-IR and sub-microwave electrooptic applications.