Capability Maturity Model Integration (CMMI) is a process level improvement training and appraisal program. Administered by the CMMI Institute, a subsidiary of ISACA, it was developed at Carnegie Mellon University (CMU). It is required by many U.S. Government contracts, especially in software development. CMU claims CMMI can be used to guide process improvement across a project, division, or an entire organization.

CMMI defines the following five maturity levels (1 to 5) for processes: Initial, Managed, Defined, Quantitatively Managed, and Optimizing. CMMI Version 3.0 was published in 2023; Version 2.0 was published in 2018; Version 1.3 was published in 2010, and is the reference model for the rest of the information in this article. CMMI is registered in the U.S. Patent and Trademark Office by CMU.

Originally CMMI addresses three areas of interest:

In version 2.0 these three areas (that previously had a separate model each) were merged into a single model.

CMMI was developed by a group from industry, government, and the Software Engineering Institute (SEI) at CMU. CMMI models provide guidance for developing or improving processes that meet the business goals of an organization. A CMMI model may also be used as a framework for appraising the process maturity of the organization. By January 2013, the entire CMMI product suite was transferred from the SEI to the CMMI Institute, a newly created organization at Carnegie Mellon.

CMMI was developed by the CMMI project, which aimed to improve the usability of maturity models by integrating many different models into one framework. The project consisted of members of industry, government and the Carnegie Mellon Software Engineering Institute (SEI). The main sponsors included the Office of the Secretary of Defense (OSD) and the National Defense Industrial Association.

CMMI is the successor of the capability maturity model (CMM) or Software CMM. The CMM was developed from 1987 until 1997. In 2002, version 1.1 was released, version 1.2 followed in August 2006, and version 1.3 in November 2010. Some major changes in CMMI V1.3 are the support of agile software development, improvements to high maturity practices and alignment of the representation (staged and continuous).

According to the Software Engineering Institute (SEI, 2008), CMMI helps "integrate traditionally separate organizational functions, set process improvement goals and priorities, provide guidance for quality processes, and provide a point of reference for appraising current processes."