The swimmer, who won three gold medals at the Rio Games last year, received the award at Buckingham Palace.
Her golden hat trick came with wins in the 100m backstroke,the 200m freestyle gold and the women's SM14 200m individual medley.
The 100m backstroke win to retain her London 2012 title set a new record.
At the Brazil Games, she also won silver in the 100m breaststroke, the weakest of her four events.
The 21-year-old from Seaforde in County Down competes in the S14 class for swimmers with an intellectual disability.
Northern Ireland's four-time Paralympic gold medal-winning swimmer Bethany Firth has been recognised with an MBE.