It is the purpose of this thesis to set forth clearly and objectively the concept of sanctification as it was believed and taught by John Wesley. Concept is used to indicate thought or opinion or view. Sanctification is used in the narrow sense to mean the conduct of the Christian life or holiness of living which follows justification. This concept of sanctification will be limited to its doctrinal content and characteristics with a survey of influences which affected it in one way or another. No attempt is made to trace the social and political implications of this teaching, except in so far as they touch upon the doctrinal background. Finally a brief summary and evaluation of the teaching are given