The US aircraft maker has also agreed to spend nearly $2 billion on reciprocal deals, they said.
"Boeing has a counter trade ... amounting to 85 billion rupees ($1.9 billion) over the next 10 years, which would mean that Boeing will buy from India a range of goods and services," Civil Aviation Minister Praful Patel said in Mumbai on Wednesday after the formal signing.
The pact, which has been years in the making and got the final nod by the government in December, was signed by Air India chairman V Thulasidas and Boeing Commercial Airplanes president Alan Mulally.
The aircraft maker would also spend $75 million in pilot training and $100 million in maintaining and repairing the aircraft, Patel told reporters.
"The aircraft, valued at more than $11 billion at list price, are scheduled for delivery beginning November this year," said a statement issued at the media conference.
"Air India's order consists of 23 777s, 27 787-8 Dreamliners and 18 next-generation 737-800s."
Mulally, meanwhile, said there would be a small price discount offered to Air India but declined to give details.