A high-strength galvanized steel sheet comprising a base steel sheet and a galvanized layer on a surface of the base steel sheet, wherein the base steel sheet has a chemical composition containing, by mass%, C: 0.12% to 0.35%, Si: 0.5% to 3.0%, Mn: 1.5% to 4.0%, P: 0.100% or less and not including 0%, S: 0.02% or less and not including 0%, Al: 0.01% to 1.50%, and optionally at least one selected from Cr: 0.005% to 2.0%, Ni: 0.005% to 2.0%, Cu: 0.005% to 2.0%, V: 0.1% to 1.5%, Mo: 0.1% to 1.5%, Ti: 0.005% to 0.10%, Nb: 0.005% to 0.10%, B: 0.0001% to 0.0050%, Ca: 0.0003% to 0.0050%, REM: 0.0003% to 0.0050%, Sn: 0.005% to 0.50%, Sb: 0.005% to 0.50%, and Zr, Mg, La, and Ce to a total amount of 0.002%, with the balance being Fe and inevitable impurities, and wherein the base steel sheet has a microstructure in which an area fraction of martensite is 30% or less, an area fraction of pearlite is 1% or less, a total area fraction of tempered martensite and carbide-containing bainite is 30% or more and 99% or less, an area fraction of retained austenite is 1% to 20%, and a total area fraction of ferrite and non-carbide-containing bainite is 45% or less in the steel sheet microstructure in a region from a position located 300 μm from the steel sheet surface to a position located 400 μm from the steel sheet surface, and in which an area fraction of retained austenite grains having two or more crystal orientations is 40% or less in all the retained austenite grains in a region from a position located 300 μm from the steel sheet surface to a position located 400 μm from the steel sheet surface, wherein an austenite grain having two or more crystal orientations is a grain formed by a combination of plural austenite sub-grains having a misorientation of 15° or more, wherein the microstructure is measured as described in the description. the base steel sheet has a chemical composition containing, by mass%, C: 0.12% to 0.35%, Si: 0.5% to 3.0%, Mn: 1.5% to 4.0%, P: 0.100% or less and not including 0%, S: 0.02% or less and not including 0%, Al: 0.01% to 1.50%, and optionally at least one selected from Cr: 0.005% to 2.0%, Ni: 0.005% to 2.0%, Cu: 0.005% to 2.0%, V: 0.1% to 1.5%, Mo: 0.1% to 1.5%, Ti: 0.005% to 0.10%, Nb: 0.005% to 0.10%, B: 0.0001% to 0.0050%, Ca: 0.0003% to 0.0050%, REM: 0.0003% to 0.0050%, Sn: 0.005% to 0.50%, Sb: 0.005% to 0.50%, and Zr, Mg, La, and Ce to a total amount of 0.002%, with the balance being Fe and inevitable impurities, and wherein the base steel sheet has a microstructure in which an area fraction of martensite is 30% or less, an area fraction of pearlite is 1% or less, a total area fraction of tempered martensite and carbide-containing bainite is 30% or more and 99% or less, an area fraction of retained austenite is 1% to 20%, and a total area fraction of ferrite and non-carbide-containing bainite is 45% or less in the steel sheet microstructure in a region from a position located 300 μm from the steel sheet surface to a position located 400 μm from the steel sheet surface, and in which an area fraction of retained austenite grains having two or more crystal orientations is 40% or less in all the retained austenite grains in a region from a position located 300 μm from the steel sheet surface to a position located 400 μm from the steel sheet surface, wherein an austenite grain having two or more crystal orientations is a grain formed by a combination of plural austenite sub-grains having a misorientation of 15° or more, wherein the microstructure is measured as described in the description.