Luton's Blue Square Bet Premier play-off hopes took another hit with defeat at Braintree.
The Iron went ahead when Adam Bailey-Dennis flicked Pat O'Connor's free-kick over Luton keeper Mark Tyler.
Andre Gray slotted in an equaliser soon afterwards with new manager Paul Buckle looking on from the stands.
Sean Marks' free header restored the lead, before Billy Gibson secured the points from the penalty spot after Marks was fouled by Curtis Osano.
Luton are without a win in six games and are three points behind fifth-placed Kidderminster, with two games in hand.
Braintree remain in 12th, six points below Cambridge and five points ahead of Barrow.