Jack Hunt's superb last-gasp equaliser preserved Huddersfield's 20-match unbeaten run and denied Peterborough all three points.
Grant McCann put Posh ahead from the spot just before the break after Lee Peltier felled Craig Mackail-Smith.
Hunt was then fouled in the box by James Wesolowski, but Joe Lewis superbly saved Gary Roberts' penalty.
Taking on the scoring mantle himself, Hunt jinked his way past two defenders and blasted low into the net for 1-1.
The hosts may have kept their long unbeaten run intact but they dropped down to third in the League One table after Southampton's win at Leyton Orient.
Peterborough remain in fourth place, three points behind both today's opponents and the Saints.
Huddersfield Town manager Lee Clark told BBC Radio Leeds:
"It's so late in the game the equaliser it feels a little bit like a victory.
"Certainly when you miss the penalty so late on you think that's it but credit to the lads they kept believing and kept having a go.
"First half we just let Peterborough dictate the game and their good players got on the ball too often even from the first minute.
"In the 20 games [unbeaten] we haven't had to have a heated conversation at half time to make sure we got fired up."