Ost-Indiya (anglisi East Indies — Hindustoni Sharqi), istilohest, ki dar guzashta ba territorihoi Hinduston va baze mamlakathoi Osiyoi Janubi va Janubi Sharqi nisbat doda meshud. Ost-Indiya ba muqobili istilohi Vest- Indiya ba vujud omada bud.
Evropoiho, ki jazirahoi dar bahri Karib (Amerika) kashfkardai Xristofor Kolumbro ishtibohan «Hinduston» gumon karda budand, badi az Evropa ba samti sharq sayohat kardan Hindustoni haqiqiro yofta, ba on Ost-Indiya nom dodand.