Osawe will stay for an initial month with Stanley hoping to extend the deal. The 19-year-old will go straight into their squad for the weekend's game with Bristol Rovers.
"I'm happy with the move," Osawe told the club's official website. "My manager told me that Accy were interested and I told him that I'd love to come here.
"Last year I came to watch some of the games so I know how Accy play and I'm happy with the club."
Osawe was helped to make his mind up when former Stanley loanee Micah Evans spoke to him about life at The Crown Ground following his loan spell there.
"Micah Evans has been here in the past and I asked his advice. He told me that it's a really good club, everyone's nice and they play good football."
Osawe has yet to make his first-team debut for Blackburn, but has been a regular at reserve-team level.