The Douglas O-38 was an observation airplane used by the United States Army Air Corps. Between 1931 and 1934, Douglas built 156 O-38s for the Air Corps, eight of which were O-38Fs. Some were still in service at the time of the Pearl Harbor Attack in 1941. The O-38 is a modernized derivative of the O-25, itself a re-engined variant of the earlier Douglas O-2.