The club's board had set a time limit in its search for investment and said King Power "was the only bidder who made a clear and coherent proposal".
OHL’s board has said in a statement that this the deal "guarantees the future of the club, both financially and in sporting terms".
OH Leuven were relegated from the Belgian First Division at the end of the 2015-16 season. The club says that new ownership will provide "sufficient financial resources to aspire to the earliest possible return".
The Thai group King Power that was founded by the Leicester City chairman Vichai Srivaddhanaprabha in 1989 will fund an expansion of OHL youth football work.