Gatland led the Lions to victory in Australia in 2013, and although they picked up a creditable draw in New Zealand this summer, he came in for some heavy stick.
Not only did the New Zealand media criticize, there was also discontent among the squad, and Gatland says he will not risk more of the same when they travel to South Africa in 2021.
"I'm done. Let someone else reinvent the wheel," he said. "I hated the tour. I did. I just hated the press and the negativity in New Zealand.
"When I look back on it now, there were a lot of things that were satisfying and what an achievement it was, but it was tough work. It was hard."
When pushed over whether he would be prepared to take charge for a third time in 2021, he added: "I wouldn't subject myself to that.
"What I've learned from my Lions experiences is how difficult it is to put some continuity together in terms of people and staff, and the lack of preparation time. Let someone else do it."