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 IDX Systems, a software company, portions now owned by GE and athenahealth The ICAO airline code for Indonesia AirAsia X Indonesia Stock Exchange IDX Channel, an Indonesian channel jointly owned by Indonesia Stock Exchange and MNC Media IDX Composite, the Indonesia Stock Exchange composite index Intact dilation and extraction, an abortion procedure Internet Data Exchange