Peebles took the lead when Dale Richardson latched onto a well-worked corner kick to go in at the break 1-0 up, having had the majority of the first half posession.
The hosts doubled their tally only three minutes after the restart when Frankie Arthur converted a rather questionable penalty award.
After some great passages of play Peebles got their third when Scott Sutherland finished off an excellent move.
Donovan Ndiweni completed the scoring after a fantastic shot from 20 yards forced the Ormiston keeper to spill the ball for him to tap in from close range.
Ormiston came back into the game in the closing 15 minutes but Peebles managed to keep a clean sheet until the final whistle sounded.
“It was great to put in such an exciting performance at our last home game of the season and I would like to thank all the local people who have turned out to support us this term,” said happy coach John O’Hara.