Brigadier Ivan Simson, OBE (14 August 1890 – 4 February 1971) was a British Army officer and the Chief Engineer in Malaya from August 1941 until its surrender to the Japanese in 1942. Simson was tasked with improving the defenses in Singapore in the face of possible attack by the Japanese, although Simson's defensive recommendations were largely rejected by his commander, Lieutenant General Arthur Percival, as being bad for morale.^[1] Previously he was Deputy Chief Engineer Scottish Command.^[2]

The Battle of Singapore from 8 to 15 February resulted in a decisive Japanese victory and the capture of Percival, Simson, and the majority of troops under them.^[3]