In an attempt to identify an active material for use in lithium secondary batteries with high energy density, we investigated the electrochemical properties of gallium (III) sulfide (Ga2S3) at 30°C. Ga2S3 shows two sloping plateaus in the potential range between 0.01V and 2.0V vs. (Li/Li+). The specific capacity of the Ga2S3 electrode in the first delithiation is ca. 920mAhg−1, which corresponds to 81% of the theoretical capacity (assuming a 10-electron reaction). The capacity in the 10th cycle is 63% of the initial capacity. Ex situ X-ray diffraction and X-ray absorption fine structure analyses revealed that the reaction of the Ga2S3 electrode proceeds in two steps: Ga2S3 +6Li+ +6e− ⇆2Ga+3Li2S and Ga+ xLi+ + xe− ⇆Li x Ga.