The school was founded in 1982. Initially named as "The Tung Wah Hospital No. 12 College” and it was named as "The Tung Wah Hospital Li Ka Shing College” in honour of Mr. Li Ka Shing , who made a generous donation of three million dollars towards educational equipment and teaching aids in 1984. The school commenced operation in the premises of “TWGHs Kap Yan Directors' College” in Choi Yuen Estate ,Sheung Shui from 1982-1984. In July 1984, it was moved to the newly completed premises in Cheung Wah Estate, Fanling. 

本校創辦於一九八二年九月，初時命名為「東華三院第十二中學」。一九八二年至八四年，本校暫借上水彩園邨「東華三院甲寅年總理中學」上課，於一九八四年校舍建校工程完竣，七月正式遷入祥華邨新校舍上課。蒙殷商李嘉誠先生慨捐三百萬元作為設備及教具費用，董事局遂將本校命名為「東華三院李嘉誠中學」。