Rotherham striker Lewis Grabban had a goal ruled out as Gillingham ended a run of five successive league defeats.
Gillingham had opportunities to score early on with the best falling to Jo Kuffour but he smashed his shot wide when one on one with Rhys Taylor.
Grabban thought he had put the Millers ahead, but the striker was penalised for a handball.
Rotherham's Alex Revell had a great chance, but put his shot went wide as the League Two contest ended goalless.
VIEW FROM THE DRESSING ROOM
Gillingham manager Andy Hessenthaler told BBC Radio Kent:
"I think it's a really big point tonight, reasons being the run we've been on and the pressure we've put on ourselves.
"A draw was a fair result but we created the better chances. They're a difficult side to play against and we defended very well tonight.
"I wouldn't disregard us from the play-offs. People might laugh but we've got 16 games to go and we've got great togetherness."
Rotherham United manager Andy Scott tells BBC Radio Sheffield:
"We are very disappointed that we've only got a point because, in the second half, we were the only team that was going to win it. Numerous chances, balls flashing across the box. We just couldn't get the final touch.
"But our play was terrific at times and we passed the ball very well second half. We coped with their formation and they were always going to come out fast at us.
"They had to perform. They've been under a lot of pressure. They've not been getting the results they wanted and we know how hard that and always knew it was going to be a tight one."