Wednesday extended their unbeaten run in the Championship to four matches but were given a helping hand by referee Mick Russell.
Wednesday should have been reduced to 10 men midway through the first half when key player Jeremy Helan was shown a second yellow card.
But Russell did not realise he had already booked the on-loan Manchester City midfielder and amid furious protestations from Huddersfield players and management, the Herefordshire official allowed Helan to play on.
Huddersfield almost snatched all three points in the final minute when substitute James Vaughan flashed a volley inches wide.
But Wednesday substitute Mamady Sidibe forced Huddersfield goalkeeper Alex Smithies into a superb save with a header moments earlier and a draw was a fair reflection of an entertaining encounter.
The visitors spurned a golden chance to take an early lead when Helan squeezed between two defenders into the penalty area only to see his low shot saved by the feet of Smithies.
Referee Russell then booked Helan for a 26th-minute foul on Hammill. The official seemingly forgot he had already shown the Frenchman a yellow card for diving in the penalty area 17 minutes earlier, but despite animated reminders from home players and the Town bench, Russell allowed Helan to play on.
Amid chants of 'you don't know what you're doing' the referee's gaffe was also pointed out by Grayson to fourth official Duncan Street and assistant referee Wayne Grunnill, but under the laws of the game, once Russell had restarted play following the foul, he was unable to retrospectively correct his mistake.
Town carved out their only clear-cut chance of the opening half a minute before the interval. Church's low shot following Adam Clayton's cross was brilliantly saved by Wednesday goalkeeper Chris Kirkland and the score remained goalless at half-time.
Wednesday winger Michail Antonio almost cashed in on Wallace's slip on the edge of the area a minute into the second period, but dragged his shot wide.
Wednesday substitute Sidibe lashed a 25-yard shot high and wide in the 84th minute before Sidibe's header from Rhys McCabe's corner was superbly tipped away by Smithies and Vaughan's volley shaved the post at the other end.