The order is worth $2.27 billion at Boeing's list prices, although customers typically receive a discount.
The deal is equally split between 737-800 and 737 Max 8 aircraft, to be delivered over three years from 2018, BOC said. The 737 Max is the upgraded version of the 737, offering greater fuel efficiency and lower operating costs.
Boeing, in a separate statement, said it will add the planes to its order book when the deal is finalized.
The latest deal is in addition to BOC Aviation's August 2014 order for 82 Boeing jets worth $8.8 billion at list prices, comprising 50 737 Max aircraft, 30 737-800s and two 777-300ER wide-body jets.
The Singapore-based lessor also ordered 43 Airbus A320 family of aircraft in July last year, including seven A320neo planes.
BOC Aviation said it had commitments to acquire 203 aircraft as of Sept. 30. Its portfolio comprises 253 owned and managed aircraft, operated by 59 airlines globally.
Airlines are increasingly reliant on lessors such as BOC Aviation as they seek to lower capital costs.
(Siva Govindasamy - Reuters)