Snowboarder Gillings-Brier, 30, and cyclist Kennaugh, 25, were named Sportswoman and Sportsman of the Year at a ceremony on Thursday.
Kennaugh, from Douglas, won silver in the men's points race at the 2014 Commonwealth Games in Glasgow.
Gillings-Brier, from Ronague, was awarded for her performance at the 2014 Winter Olympics in Sochi.
In other categories, Manx TT rider Connor Cummins won the Isle of Man Ambassador Award, while Team GB cyclist Jake Kelly was named Under-21 Sportsman of the Year.
Youth Olympic silver medallist Charlotte Atkinson took the female Under-21 award.
Swimming dominated in the Coach of the Year and Disability Sportsperson of the Year categories, with Lee Holland and Ben Grainger respectively picking up those awards.
The Isle of Man's Commonwealth Games Women's Gymnastics Team won in the Team of the Year category and Leonie Cooil was announced as the Administrator of the Year for 2014.
The new category introduced this year was Veteran Sportsperson and this was won by TT sidecar rider Dave Molyneux.
Ian Harrop was given the 2014 Lifetime Achievement award in recognition for his work with the Isle of Man Commonwealth Games Association, while disability athlete Zoe Lambie was presented with a Special Achievement award recognising her accomplishment finishing the 2014 Parish Walk in a time of 22 hours and 32 seconds.
Gary Corkhill, the executive chairman of Isle of Man Sport, said: "We've had many great success stories during 2014 and they have been recognised here tonight.
"The evening is a fantastic showcase for our sports stars, so many of whom are now competing at the highest level."
Peter Kennaugh and Zoe Gillings-Brier have scooped the top honours at the Isle of Man Sports Awards 2015.