During the thirties, the Royal Iraqi Air Force purchased numerous aircraft from various countries. Among these purchases were 16 Gladiator Mk.Is from RAF M.E. stocks. Nine were delivered in 1937 and seven in 1938. The received serial numbers 79-94. By 1940, serial nos. 80, 85, 86, 90 and 91 had been written off. ; although the exact date of purchase remains a mystery.
The aircraft were based at Mosul and Rashid and were maintained by RAF at Habbaniyah Aircraft Depot.

The Iraqi aircraft took part in the attacks on RAF Habbaniyah in May 1941during the Iraqi revolt. The Gladiators came from 4 (Fighter) Squadron, which operated 10 Gladiators (seven operational) initially from Hurriyah.
During this revolt, the Iraqi Gladiators claimed one victory by 1st Lieutenant Abdul Salam Yahya al-Katib.
At least two Gladiators were lost due to enemy action during the revolt while a third was lost in a take-off accident.

Some of the aircraft were later returned to the RAF.

On 1 March 1944, five ex-RAF M.E. Gladiator Mk.IIs were delivered as replacement aircraft from RAF stocks at Habbaniyah. Two of these aircraft are known to have been airworthy at Mosul in 1949.

Known Iraqi Gladiators:
RAF serials:
K6140, K6141, K6147, K7897, K7907, K7928, K7954, K7961, K7983, K7988,
K7989, K8005, K8006, K8007, K8011, N5780, N5825, N5827, N5828, N5830,
N5857.
Notes:
Most of the aircraft listed were delivered after the Iraqi Revolt. At the moment, the serials of the initial batch of 15 aircraft bought from Britain during the late thirties are unknown, although they may include K6140, K6141, K6147, K8005-K8007 and K8011.
K6140; delivered from ‘X’ Flight and returned to 1412 (Met) Flight RAF on 01/01/42.
K6141; returned to RAF.
K6147; delivered from 261 Sq. and returned to 1415 (Met) Flight RAF in 03/42.
K7897; loaned from 33 Sq. on 12/10/40. SOC as crashed 06/07/41 (495 hrs).
K7907; delivered 06/12/42 from ‘X’ Flight.
K7928; delivered in 06/12/42 from 119 MU.
K7954; loaned from 33 Sq. on 12/10/40. Returned to ‘X’ Flight on 06/06/41.
K7961; delivered 06/44 from 1411 (Met) Flight RAF.
K7983; delivered in 1944 from 1413 (Met) Flight RAF.
K7989; delivered in 31/03/43 from 119 MU.
K8005; delivered directly from Manufacturer to the Iraqi Air Force.
K8006; delivered directly from Manufacturer to the Iraqi Air Force.
K8007; delivered directly from Manufacturer to the Iraqi Air Force.
K8011; delivered 04/41 from 80 Sq.. SOC on 21/06/41.
N5780; delivered on 01/06/43 from ‘X’ Flight.
N5825; delivered on 01/03/44.
N5827; delivered in 1941.
N5828; delivered on 01/03/44.
N5830; delivered on 01/03/44.
N5857; delivered on 01/03/44 from ‘X’ Flight.

Source:
Gloster Gladiator Home Page - Alexander Crawford.
Wings of Iraq: Volume 1: The Iraqi Air Force, 1931-1970 – Milos Sipos and Tom Cooper, 2020 Helion & Company Limited, ISBN 978-1-913118-74-7
Royal Air Force Aircraft L1000-N9999 - James J. Halley, 1993 Air-Britain (Historians) Ltd, Kent, ISBN 0-85130-208-4
The Gloster Gladiator - Francis K. Mason, 1964 Macdonald & Co. Ltd. London
Additional information kindly provided by Börje Henningsson