Tems stood out at the Oscars, blocking the view of people sitting behind her ... and while the folks there were polite, Twitter gave her an earful.

The Nigerian singer -- who was on hand Sunday for her musical work on 'Wakanda Forever' -- had one of the more noticeable getups at the award show ... a massive white dress that was jutting out and upward at her shoulders, which made her look like a human flower.

The problem ... when she sat down, her 'fit sorta caused a big distraction -- both onscreen for viewers, and certainly for everyone else sitting in the rows behind her.

During the broadcast, there were several moments where you could see the people right behind Tems peering over her shoulder to get a glimpse of the stage or of Kimmel. It was pretty funny ... they were obviously challenged by her dress and had to do peek-arounds to see the action. It doesn't appear anyone said anything to her.

The same can't be said for the bird app ... 'cause a lot of users there were pretty angry at the fact that she wore something so big, and which would presumably cause some blind spots in the theater. A bunch called it "rude" ... others found it hilarious. Mixed bag.