Silapakorn University president Chaicharn Thavaravej resigned on Monday after photos of female aircrew posted on his Facebook account stirred a public outcry.
Mr Chaicharn said he decided to step down to protect the image and reputation of the university.
Mr Chaicharn's pictures of air hostesses on flights he took went viral on social media last Wednesday.
In a description accompanying the pictures taken in the cabin of a plane, he wrote he always took photos of hostesses to show to his junior colleagues to make their "mouths water".
A network of 21 women's organisations on Saturday demanded that the university take action against the president, saying the photos and the message amounted to sexual harassment.
In the resignation letter, Mr Chaicharn admitted he had posted the photos and "inappropriate messages" online. But he said he had no intention of harming anyone.
