The Douglas O-53 Havoc was to have been a heavy observation aircraft based on the A-20 Havoc, but a large order was cancelled before any had been built.
On 2 October 1940 an order was placed for 1,489 O-53 observation aircraft, with serials 41-3670 to 41-5158. These were to be similar to the A-20B and built alongside them on the Long Beach production line. The A-20B was powered by two 1,600hp Wright R-2600-11 engines and had a modified glazed nose.
The order was cancelled before a single aircraft had been built, after the USAAF decided it no longer required heavy observation types. This ended the long line of Douglas observation aircraft that had begun with the O-2 biplane of 1924.