Authorities in the town of Baghpat, Uttar Pradesh state, arrested the mothers Friday, the BBC reported. They had not yet formally responded to the charges.
The victims, Zahida, 19, and Husna, 26, fell in love with two Hindu construction workers and got married. When they returned home last week to make peace with their families, they were strangled, police said.
Hindu-Muslim marriages are frowned upon by both communities in rural India.
"How could they elope with Hindus? They deserved to die. We have no remorse," the Indian Express newspaper reported one of the mothers said after being arrested.
Just last week, the Indian Supreme Court approved the death penalty for people convicted of "honor killings," which a recent study found number in the hundreds annually.
"It is time to stamp out these barbaric, feudal practices which are a slur on our nation," the justices said.