Guru Tegh Bahadur Nagar (GTB Nagar), formerly known as Koliwada, is a neighbourhood in Sion, Mumbai, named after Sri Guru Tegh Bahadur Ji, the ninth Guru of Sikhism.

Originally home to Mumbai's indigenous Koli community, it is also known as Koliwada. A colony was constructed for the rehabilitation of Sikh and Hindu refugees who came from North West Frontier Province of Pakistan after the Partition of India

Today, many of the buildings and tenements originally constructed for the refugees are in a dilapidated state, and are awaiting demolition and redevelopment.

The neighborhood's residents, however, have been protesting the order to vacate the property and its subsequent demolition because they are looking for a different rental and redevelopment arrangement.

GTB Nagar, today, is renowned for its unique culture and cuisine, which has evolved over the years as an amalgamation of the influences of the indigenous Koli community and the Punjabi Hindu and Sikh migrants.