The Earth System Modeling Framework (ESMF) is high-performance, flexible software infrastructure for building and coupling weather, climate, and related Earth science applications. The ESMF defines an architecture for composing complex, coupled modeling systems and includes data structures and utilities for developing individual models.

The basic idea behind ESMF is that complicated applications should be broken up into coherent pieces, or components, with standard calling interfaces. In ESMF, a component may be a physical domain, or a function such as a coupler or I/O system. ESMF also includes toolkits for building components and applications, such as regridding software, calendar management, logging and error handling, and parallel communications.