Floyd, a 46-year-old black man, died a week ago after being restrained by a police officer who kneeled on his neck for almost nine minutes.
Footage of the incident went viral and has sparked scenes of civil unrest across the US, which has been met with the threat of military action by President Donald Trump.
"When 4 black THUGS commit a crime, if 1 person commits murder, they ALL get charged & CONVICTED. When white THUGS/COPS KILL innocent black people, ALL 4 of them are responsible!!!!!!" wrote Minaj alongside pictures honouring other victims of racial violence.
"They all watched an unarmed man die and did nothing!! Why do they have different rules?????
"Let your voice be heard. Be angry. White people have been using violence against us since the beginning of time. We didn't invent violence & looting. Will these officers actually get convicted? Probably not. Let your voice be heard."