Speaking on his flight home from Armenia on Sunday he said he agreed with his adviser German Cardinal Reinhard Marx who said gay people deserved an apology in the wake of the Orlando gay club attack.
The pontiff responded with a variation of his famous "Who am I to judge?" comment and a repetition of church teaching that gays must not be discriminated against but treated with respect.
He said LGBT (lesbian, gay, bisexual and transgender) people must not be discriminated against but treated with respect.
He added: "Someone who has this condition, who has goodwill and is searching for God, who are we to judge?
"We must accompany them.
"I think the church must not only apologise ... to a gay person it offended, but we must apologise to the poor, to women who have been exploited, to children forced into labour, apologise for having blessed so many weapons."
He said families who faced divorces or other problems also needed support.
Francis then met lesbian, gay and transgender Christians and responded to claims he supported anti-same-sex marriage campaigner Kim Davis during his US visit.
He said the only personal meeting he held in Washington was with his gay former student and his partner.
