The family was returning to Varanasi yesterday when their two-wheeler collided with the tanker coming from the opposite direction, Kerakat Police Station in-charge Prashant Srivastava said.
The deceased were identified as Subhash Chandra (45), his wife Vidyawati (38) and son Harshvardhan (9), he said.
Following the incident, locals blocked the road leading to the village in protest. The blockade was lifted after police pacified the agitators, Srivastava said.
The bodies have been sent for postmortem, he said.