The quartet was abducted at a checkpoint near the city of Sirte, where they work as university lecturers.
The Islamic State (IS) group has established an imposing presence in Sirte, hometown of former leader Muammar Gaddafi.
Libya has descended into a near state of anarchy since Gaddafi's death in Sirte in October 2011, with various militias fighting for power.
The teachers, who hail from the southern Indian states of Karnataka and Andhra Pradesh, were working with the University of Sirte.
They were kidnapped on their way back to India on Wednesday.
"They were returning to India via Tripoli and Tunis, when they were detained at a checkpoint approximately 50km (31 miles) from Sirte," an Indian foreign ministry spokesperson said.
It is still not clear who kidnapped the teachers, but the spokesperson said the Indians "have been brought back to the city of Sirte".
"We are in regular touch with the families concerned and all efforts are being made to ensure the well-being and early release of the four Indian nationals," India's foreign ministry said in a statement.
Most of Sirte, former leader Muammar Gaddafi's hometown, fell to IS in May.
Last July a group of 65 Indian nurses were trapped in fighting which engulfed parts of Libya.
The nurses, who had been working in various hospitals in the country, safely returned to India in August.
In June 2014, 40 Indians - all construction workers - were kidnapped in the violence-hit Iraqi city of Mosul. Their fate is still not known.
