Ocean earlier posted a letter on his Tumblr page talking about his experiences of being in love with a man and expressing hope that "the babies born these days will inherit less of the bulls**t than we did".
Simmons has now responded to Ocean's note, declaring in a blog for Global Grind that "today is a big day for hip-hop".
"I am profoundly moved by the courage and honesty of Frank Ocean," he said. "Your decision to go public about your sexual orientation gives hope and light to so many young people still living in fear.
"These type of secrets should not matter anymore, but we know they do, and because of that I decided to write this short statement of support for one of the greatest new artists we have."
Simmons added that Ocean has "undeniable" gifts, "enormous" talent and "incredible" bravery, saying: "His actions this morning will uplift our consciousness and allow us to become better people. Every single one of us is born with peace and tranquility in our heart. Frank just found his."
Simmons, who linked to the blog on his Twitter page by saying that "the courage of Frank Ocean just changed the game", concluded: "Frank, we thank you. We support you. We love you."
Odd Future member Tyler, the Creator has already tweeted his support for Ocean, saying that he is "proud".