Wal-Mart said the iPad will be available in hundreds of its stores in the United States to start, expanding to more than 2,300 outlets by mid-November.
Wal-Mart rivals Best Buy and Target are already selling the iPad, which Apple launched in April.
Demand for the 10-inch touchscreen tablet has so far been robust, and Apple initially had a difficult time producing enough.
The company sold more than 3 million iPads in the June quarter, and Wall Street expects the company to surpass that mark with ease in the September quarter.
Apple is set to report quarterly results next Monday.
Wal-Mart will sell the iPad for the same price as other retailers, starting at $499 for the more inexpensive model. The world's largest retailer already sells Apple's iPod and iPhone.
Shares of Cupertino, California-based Apple were up $1.75 at $297.11 in midday trading on the Nasdaq.