IWT may refer to:

• Ifor Williams Trailers, Manufacturer of trailers up to 3500kg
• Indus Waters Treaty, a water-sharing treaty between the Republic of India and Islamic Republic Of Pakistan
• Institute for the promotion of Innovation by Science and Technology, in Flanders, Belgium

• Heterostasis extricata
• Heterosteca
• Heterostega curtipendula
• Heterostegane minax
• Heterostegane ruberata
• Heterosteidae
• Heterostemma
• Heterosternuta
• Heterostigma
• Heterostracans
• Heterostructures
• Heterostylus
• Heterosubtypic
• Heterosubtypic Immunity
• Heterosubtypic immunity
• Heterosynaptic Plasticity
• Heterosynaptic plasticity
• Heterotactic
• Heterotactis quincuncialis
• Heterotaxalus
• Heterotaxalus schwarzeri
• Heterotaxia
• Heterotaxia (generic term)
• Heterotaxis
• Heterotaxis crassifolia