Rihanna's Rare Photo with Mom and Dad Together

Rihanna's third wheeling it back home, but couldn't look happier about it because she's hanging with Mom and Dad -- a rare sighting of the fam together.

RiRi's grinning in the shot with her mother, Monica, and father, Ronald. We don't know exactly what's behind the reunion, but she captioned the shot, "home" -- so, we're guessing she's in Barbados.

That she posted this pic is huge. Remember, Rihanna had a fractured relationship with her father ... telling Oprah in 2012 she had to make peace with her abusive father before she could forgive Chris Brown for assaulting her in 2009.

Rihanna said she struggled with the fact her dad was loving to her, but physically abused her mom. Seems the whole family is on the mend.