Theories form the broad basis for our understanding of learning. They provide a direction to our thinking and action to develop an appropriate design for learning and teaching. Theories of learning are closely related to human behavior and have been around for about a century. However, many other theories have developed recently, treating instructional design as a distinct field.

 A theory is a set of systematically interrelated hypotheses, premises, assumptions, facts, and observations pertaining to a particular phenomenon. Theories help us to organize, explain, and predict our observations and experiences on learning. They also help us to generate new hypotheses. Theories also raise certain mysteries or questions which are not verified and help us delve deeper into the subject of learning.

Theories are often termed as "points of view" since observations could be the same for many types of research, interpretation of these could vary widely resulting in different perspectives and explanations of results.