The car the six family members were travelling in rammed into a tree as the person who was driving it lost control while trying to avoid hitting a motorcycle coming from opposite direction.
Police said they were going to visit their relatives on the occasion of Raksha Bandhan festival tomorrow.
The deceased were identified as Manpreet Singh (25), his brother's wife Gurmeet Kaur (30) and Manpreet's one-year-old son Harjot Singh.
Injured were Manpreet's wife Gaganpreet Kaur, son of Manpreet's brother Samarpreet Singh and another family member Damanpreet Kaur.