The Buddhist monk offered his views on the issue during his latest tour of the United States, where he was welcomed on Thursday in Washington by top politicians and offered the customary prayer that opens each Senate session.
He said that gay marriage was up to each government and was ultimately "individual business".
"If two people - a couple - really feel that way is more practical, more sort of satisfaction, both sides fully agree, then OK," he told an online talk show by veteran radio and television host Larry King.