Single-crystal nanosheets of magnesium hydroxide were electrodeposited from aqueous magnesium nitrate solution. SAED and in-situ dehydration study confirmed that the single-crystal Mg(OH)(2) nanosheets were grown with their {011} planes for the first time. The average transmittance of the porous Mg(OH)(2) films deposited at -1.2 V over the visible region (390-780 nm) is 90.21%, which shows high optical transparency. The continuously growing nanosheets cross each other and join up, leading to the formation of continuous porous network of thin films. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.019204jes] All rights reserved.