Abstract Consumer knowledge is important both to theoretical models of consumer behavior and to marketing practice. There are three distinct but related ways in which consumer knowledge is conceptualized and measured: objective knowledge, subjective knowledge, and experience. This paper describes the development and validation of a short, reliable, and valid self-report measure of subjective knowledge that is applicable to a variety of data collection methods and subject areas. It can be used to test consumer theories and in practical applications. Multiple studies using data from 1,178 subjects show that the scale is unidimensional, internally consistent, valid, free from methodological confounds, and easy to use.