The superstore also announced Wednesday that it will discontinue the sale of fruit and dessert-flavored nicotine.
On April 5, Walmart received a letter from the U.S. Food and Drug Administration regarding its efforts to prevent the sale of tobacco and electronic nicotine delivery systems to minors, which caused the company to reevaluate its policies, John Scudder, chief compliance and ethics officer for Walmart, said in a statement.
"Even a single sale to a minor is one too many, and we take seriously our responsibilities in this regard," Scudder said.
Walmart passed 93% of nearly 13,000 of its FDA compliance checks involving minors at its stores, according to a letter the chain sent back to the FDA on Wednesday. With the new policies, the company-wide goal will be 100%, according to the retail chain.
The new policy will go into effect across all Walmart stores in the U.S. on July 1.
Last month, Walgreens and Rite Aid announced similar initiatives to raise the minimum age to buy tobacco in their stores to 21.
Walgreens' new policy will take effect on Sept. 1, while Rite Aid's will be implemented in July.