The second-tier club, located just east of capital city Brussels, narrowly avoided relegation this season.
The club's board set a time limit in its search for investment and said King Power "was the only bidder who made a clear and coherent proposal".
Its directors said the deal "guarantees the future of the club, both financially and in sporting terms".
OH Leuven were relegated from Belgium's top tier in 2015-16 but said new ownership would provide "sufficient financial resources to aspire to the earliest possible return".
It added King Power - founded by Leicester chairman Vichai Srivaddhanaprabha in 1989 - will fund an expansion of the club's youth system.
The acquisition will be formally completed when the company has concluded due diligence.
Srivaddhanaprabha is worth an estimated £3.6bn according to Forbes.
The 58-year-old bought Leicester in 2010, with the club winning promotion to the top flight four years later and claiming the Premier League title in 2015-16.
Leicester City owners King Power International have agreed to purchase OH Leuven, the Belgian club says.