Certification refers to the confirmation of certain characteristics of an object, person, or organization. This confirmation is often, but not always, provided by some form of external review, education, or assessment. One of the most common types of certification in modern society is professional certification, where a person is certified as being able to competently complete a job or task, usually by the passing of an examination.

There are two general types of professional certification: some are valid for lifetime, once the exam is passed. Others have to be recertified again after a certain period of time. Also, certifications can differ within a profession by the level or specific area of expertise they refer to. For example, in IT Industry there are different certifications available for Software Tester, Project Manager, and Developer. Similarly, the Joint Commission on Allied Health Personnel in Ophthalmology offers three certifications in the same profession, but with increasing complexity.

Certification does not refer to the state of legally being able to practice or work in a profession. That is licensure. Usually, licensure is administered by a governmental entity for public protection purposes and certification by a professional association. However, they are similar in that they both require the demonstration of a certain level of knowledge or ability.

The other most common type of certification in modern society is product certification. This refers to processes intended to determine if a product meets minimum standards, similar to quality assurance.

Organizational certification, such as the Green Globe environmental and sustainability certification, is usually referred to as accreditation. The differentiation in terms is especially relevant with regards to the National Commission for Certifying Agencies (NCCA), which is a body that accredits certifying organizations.