IIF

IIF may refer to:


 * IIf (abbreviation for immediate if) and ?:, the inline-if computing function
 * Indirect immunofluorescence, one of several types of immunofluorescence
 * Institute of International Finance, an association of international financial institutions
 * International Indonesia Forum, an organisation which holds annual interdisciplinary seminars in Indonesia.
 * International Institute of Forecasters, a nonprofit organization devoted to advancing the science of forecasting
 * Intuit Interchange Format, a file format used by Intuit's Quickbooks software