ABAP the Advanced Business Application Programming is a programming language for developing (to tailor and enhance SAP applications) applications for the SAP R/3 system. ABAP is one of many application-specific fourth-generation languages (4GLs) first developed in the 1980s. By 2001, all but the most basic functions were written in ABAP. In 1999, SAP released an object-oriented extension to ABAP called ABAP Objects, along with R/3 release 4.5.

ABAP/4 is the language created by SAP AG for implementation and customization of their R/3 system. The rough English translation of the acronym would be A Business Application Programming language, version 4. It is a block-structured language. ABAP/4 contains some highly report-oriented event-driven control structures.