Shri Jamnalal Bajaj (4 November 1889 – 11 February 1942) was an industrialist, philanthropist, and freedom fighter.

He was born to Kaniram and Birdibai on 4th Nov, 1889, in a small village Kashi-Ka-Bas in the Sikar district. He later was adopted by Seth Bachhraj and his wife Sadibai as their grandson.

Under the guidance of Seth Bachhraj, Jamnalalji got involved in the family business and acquired the know-how of being a tradesman - keeping strict accounts and buying and selling commodities - excelling in his work. In 1926 he founded what would become the Bajaj Group of industries. Today, Bajaj Group of industries has expanded to 24 companies, including 6 listed ones.

During the First World War, the British government appointed Jamnalalji, as an honorary magistrate. When he provided money for the war fund, they conferred on him the title of Rai Bahadur.

He was a close associate and follower of Mahatma Gandhi, who was known to have adopted him as his fifth son. Jamnalalji took an interest in Gandhiji's way of life, his principles, such as Ahimsa (non-violence), and his dedication to the poor. He could understand Gandhiji's vision that homemade goods were the answer to India's poverty and strongly advocated that cause while touring the length and breadth of India promoting Khadi.

In 1920, Jamnalalji was elected chairman of the reception committee for the Nagpur Session of the Indian National Congress. He gave up the title of Rai Bahadur conferred on him by the British government and joined the Non-Co-operation Movement in 1921. Later, in 1923, he participated in the Flag Satyagraha, defying a ban on flying the National Flag in Nagpur, and was detained by British forces. This earned him National admiration. He was later elected as a member of the Congress Working Committee and, in 1933, was chosen as the Treasurer of Congress.

With the intent of eradicating untouchability, he fought the non-admission of Harijans into Hindu temples in his home town of Wardha. Amidst strong objections, he opened his own family temple, the Laxmi Narayan Mandir, in Wardha, for the Harijans in 1928. This was the first temple in India to do so.

Jamnalalji dedicated much of his wealth to the poor. He felt this inherited wealth was a sacred trust to be used for the benefit of the people. This was in line with the trusteeship concept proposed by Gandhiji. That he was Treasurer of the Indian National Congress for more than 20 years despite having just 4 years of formal education is an insight into the mind of a man who knew no limits.