Henderson will defend the title, which he won in February, against Edgar, UFC president Dana White announced Tuesday night.
"The Frankie Edgar and Ben Henderson rematch will be this summer," White said on Twitter.
No specific date or venue has been set for the fight.
White, who was in New York on Tuesday to promote UFC on Fox 3, which will be held May 5 in East Rutherford, N.J., granted Edgar the rematch after meeting with him Tuesday night. Edgar (14-2-1) resides in Toms River, N.J.
"I'm pumped, obviously. The first fight didn't go as I wanted," Edgar said. "I thought I did enough to win it, but it still didn't go my way. Now I get a chance at redemption. I'm glad Dana and (UFC co-owner) Lorenzo (Fertitta) made this choice. I feel I deserve it.
"And I had a lot of support from the fans. I thank them, too."
Henderson defeated Edgar by unanimous decision at UFC 144 on Feb. 26. The bout was scored 49-46, 48-47 and 49-46. However, each round was closely contested and many observers had Edgar as the winner.
Immediately after the fight, talk of who Henderson would face next became a hotly-contested issue.
Pettis defeated Henderson by unanimous decision in December 2010 to claim the WEC lightweight title. He is the last man to beat Henderson.
White, however, would not fully commit to a challenger for Henderson (16-2) until after speaking with Edgar. He was hoping he could convince Edgar to move down to the featherweight division before making a final decision.
"I think he belongs there (at featherweight)," White said. "It was tough before when he was beating everybody at 155 pounds.
"He's a great fighter. If the guy wants to stay at 155, I can't tell him not to."
But White was unsuccessful in changing Edgar's mind. Edgar did leave the door open to competing at 145 pounds in the future.
"I did not give moving to 145 pounds serious consideration at this time," Edgar said. "I'm not ready to do down, especially after losing a fight where it was so close.
"It was a fight where I thought I did enough to win. I didn't want to go down (to featherweight) on that note. I'd rather go on a more positive note."
According to his manager, Malki Kawa, Henderson did not hesitate when asked to fight Edgar once more.
"It's being consistent with what Ben has said -- whoever the UFC wants him to fight, he will fight," Kawa said. "Ben isn't really into picking his opponents. If (UFC) had given him Anthony Pettis, he would have fought him. But they decided to grant Edgar an immediate rematch, and Ben was very quick to accept."
Franklin McNeil covers mixed martial arts and boxing for ESPN.com. Follow him on Twitter at www.twitter.com/Franklin_McNeil.