Professor Green has said the case of Lavinia Woodward sets a precedent for how the elite could be treated by the criminal justice system.
The 24-year-old student at Oxford University was spared jail by Ian Pringle QC, who gave her a ten-month suspended sentence.
She had admitted to the unlawful wounding of her boyfriend after she stabbed him in the leg with a bread knife in a drug-induced rage.
The judge had said she was "too bright", adding that the incident appeared to be a "one-off" and a prison sentence would be too severe for an "extraordinarily able young lady."
Green, a rapper and singer, took exception to the ruling, posting about it on his Instagram page.
He told James Whale and Ash: "How can you be too bright? Is that an oxymoron, too bright for prison?
"There are people who don’t have a safety net and make a bad decision at a young age and end up in front of a judge who has no idea and cannot empathise with their background and they get put in prison.
"This ruins the rest of their lives, and yet, he’s been sympathetic to the girl who has had every privilege growing up.
"I think it sets precedent. It tells people not everyone will be treated fairly.
"It says if you are of the elite, you will be treated differently by everyone else."