ELF may refer to:

• Executable and Linkable Format, a computer file format
• Extended Log Format, standardised text format for log files
• The COSMAC ELF, a microcomputer kit

An elf (plural: elves) is a type of supernatural being in Germanic mythology and folklore. Reconstructing the early concept of an elf depends almost entirely on texts in Old English or relating to Norse mythology. Later evidence for elves appears in diverse sources such as medical texts, prayers, ballads, and folktales.

In computing, the Executable and Linkable Format (ELF, formerly called Extensible Linking Format) is a common standard file format for executables, object code, shared libraries, and core dumps. First published in the System V Release 4 (SVR4) Application Binary Interface (ABI) specification, and later in the Tool Interface Standard, it was quickly accepted among different vendors of Unix systems. In 1999 it was chosen as the standard binary file format for Unix and Unix-like systems on x86 by the 86open project.