Before his resignation, Mr Tavares was one of the most powerful people in the global motor industry.
He had a reputation as a ruthless cost-cutter, first at the French group PSA – then, following its merger with Fiat Chrysler in 2021 – at Stellantis.
He frequently made headlines in the UK by casting doubt over the future of Vauxhall operations in the UK, linking it to issues such as Brexit and government plans to force car makers to build more electric cars.
It is not yet clear whether his departure will affect the planned closure of Stellantis’ Luton plant.
Mr Tavares’ position had been undermined recently by a dramatic fall in sales and profits at the company.
Stellantis’ share price has fallen by 40% since the start of this year.
In September, the company said it had started to look for Mr Tavares’ successor, but he was expected to stay in his role until at least 2026.
Stellantis said it now expected to appoint a new chief executive by the middle of next year.
In the meantime it will set up a a new interim executive committee, led by the firm’s chairperson John Elkann.