VSI

VSI may stand for:
 * Vertical shaft impactor, a type of impact crusher
 * Vertical speed indicator, an instrument in an aircraft monitoring rate of descent or climb
 * Very Short Introductions, a series of books published by Oxford University Press
 * Virtual Switching Instance, in VPLS
 * Voluntary Service International, the Irish branch of Service Civil International
 * VMS Software Inc. A vendor/supporter of OpenVMS related software.
 * VSI Group, British dubbing and translation company
 * VSI Berlin GmbH, German subsidiary
 * VSI Translation & Subtitling BV, Dutch subsidiary
 * Vendor's Single Interest insurance, a type of insurance that only protects the lien holder, as opposed to dual coverage insurance
 * Voltage Source Inverter, DC to AC converter