Dortmund's Mario Gotze opened the scoring for the visitors when he superbly drilled in through the legs of defender Andreas Beck and past keeper Koen Casteels in the 26th minute.
Hoffenheim's Sven Schipplock, however, levelled nine minutes later, stabbing the ball in from close range.
"It was important to go into the break with the three points," Dortmund defender Mats Hummels told reporters.
"We have wasted eight or 10 points so far this season and that is frustrating. We have to improve in the second half of the season to reach our goals," said the Germany international.
Hoffenheim's sixth straight league defeat left them in the relegation play-off spot, seven points behind 15th placed VfL Wolfsburg.
"My players gave it all they had and I cannot blame anyone," said Hoffenheim interim coach Frank Kramer. "We will now discuss everything else calmly during the winter break."
