IDX

The acronym IDX may refer to:


 * .idx file extension, used by various programs to represent an index of some kind, commonly used by the DirectVobSub add-on for subtitle files
 * ID Experts Holdings, Inc., data breach response company owned by ZeroFox
 * IDX Systems, software company, portions now owned by GE and athenahealth
 * Project IDX, an online integrated development environment by Google
 * Indonesia AirAsia X, former airline with ICAO airline code IDX
 * Indonesia Stock Exchange
 * IDX Channel, Indonesian channel jointly owned by Indonesia Stock Exchange and Trans Media
 * IDX Composite, Indonesia Stock Exchange composite index
 * Intact dilation and extraction, abortion procedure
 * Internet Data Exchange