Ex-Luton Town and Hartlepool United ace Boyd hit his ninth goal of the season inside four minutes by beating Town defender David Mirfin to a loose ball.
Orient keeper Glenn Morris hit a long clearance which Terriers centre-back Nathan Clarke headed straight to Adam Chambers - who turned the ball back into the danger area.
Quick-thinking Boyd pounced just ahead of Mirfin to lash in a fine effort from just inside the box in a game Huddersfield dominated and probably should have won.
The O's only had two other serious chances, both hit straight at keeper Matt Glennon by Paul Terry from outside the area either side of the break.
Morris, making only his second start of the season in place of the dropped Stuart Nelson, was in commanding form to deny Town.
He saved twice from Luke Beckett and parried further efforts from Malvin Kamara and Danny Schofield as Huddersfield kept pressing without getting the breakthrough they deserved.
But even when they got past Morris, Tamika Mkandawire was twice there on the line to clear to safety efforts from Schofield and Kamara in the first half.
Phil Jevons, making his debut on loan from Bristol City as a substitute, nearly scored a spectacular equaliser on 71 minutes with an ambitious scissor-kick that flew just wide.
Former Yeovil and Hull star Jevons could even have equalised with the last kick of the match with six minutes of stoppage time added on for Orient's time-wasting.
Kamara's cross from the right found the unmarked Jevons inside the six-yard box - but he can be forgiven for blasting over as he is rusty, having hardly played for the Robins in the Championship this season.