Boyd, who claimed the winner when the O's and Huddersfield's met at the Galpharm last season, raced on to Sean Thornton's pass before firing past goalkeeper Matt Glennon.
The hosts pushed for an equaliser, with Gary Roberts having his goal-bound drive hacked away from the line by Orient's Stephen Purches after 17 minutes.
Huddersfield defender Joe Skarz nodded over Ian Craney's corner when well placed after 26 minutes while Michael Collins' long-range shot went inches wide.
After the interval, the Terriers continued to press forward and Collins had another shot which drifted narrowly off target.
The visitors offered little as an attacking threat and Huddersfield's Nathan Clarke should have levelled midway through the second period, but he planted his header onto the top of the net.