O'Neil was upset at his team conceding a late goal to Manchester City in the Premier League on Sunday.
Feeling that his goalkeeper was impeded in the build-up to the John Stones goal from a corner, O'Neil stated the match officials may be unconsciously biased.
He stated: "There's no chance people are purposely against Wolves - if we ever get to that, then the game's in a bad place.
"But is there something in the subconscious around decision-making? Without even knowing it, are you more likely to give it to Manchester City than Wolves?
"Referees are human, and Manchester City scoring a last-minute winner is a big thing, so maybe there's something subconsciously that you're less likely to get those decisions.
"I can tell you categorically that referees are 100 per cent honest and they are doing the best they can.
"I just know that from a human point of view, I feel different playing Manchester City than I do when we play someone in the first round of the Carabao Cup.
"I'm sure the officials feel the same. They feel it. They're human. Now, I might be miles off. But if I had to upset someone in the street and there's a big guy and a little guy, I'm upsetting the little one."
On the incident, the Premier League stated: "Stones' goal was disallowed on-field due to Bernardo Silva being in an offside position and in the goalkeeper's line of vision.
"The VAR deemed Bernardo Silva wasn't in the line of vision and had no impact on the goalkeeper and recommended an on-field review. The referee overturned his original decision and a goal was awarded."
