Mandai (IPA: /ˈmɑːndaɪ/, MAHN-dye) is a planning area located in the North Region of Singapore, famously known for being the access point for the Mandai Wildlife Reserve which includes the Singapore Zoo, Night Safari, River Wonders, Bird Paradise and Rainforest Wild.

The name Mandai appears in the Franklin and Jackson Plan of Singapore (1828) as a river indicated as "R. Mandi".

Others suggest that “Mandai” might be a corruption of mandi, meaning “bathe” in Malay, as the river could have been used for this purpose.

[3] Parts of Mandai are commonly used as military training areas as there is undeveloped land there.

Because of the massive makeover with the new bird park and rainforest park, all the military training areas (except Sembawang Air Base and Chong Pang Camp) will soon be moved to Lim Chu Kang and Pulau Tekong; and will be progressively cleared by 2023.