Dent resistance of AZ31 magnesium alloy sheets was examined under static and dynamic conditions. Dent tests were carried out for AZ31-O and AZ31-H24 sheets by using circular blanks and dent depth was measured and compared with that of aluminum alloys (1100-O, 5052-O, 5052-H34), copper alloy (C2801-O) and cold-rolled steel (SPCE) sheets. The critical punch load for initiation of the dent formation was not detected for AZ31 sheets in the punch load-stroke curves of static dent tests whereas it was clearly observed in steel sheet. In static dent tests, magnesium sheet with the lowest elastic modulus showed the largest spring back and consequently the smallest dent depth at the constant punch stroke. AZ31 sheet also showed smallest dent depth at the constant punch load. In dynamic dent tests, AZ31 sheet showed the highest dent resistance under various impact conditions. It is concluded that AZ31 magnesium sheets are suitable for various light weight panels with their excellent dent resistance as well as low density.