In this chapter, I discuss the development, piloting and revision of a new instrument for measuring pre/post the academic self-efficacy of students. The initial motivation for the creation of this new instrument came from an unsuccessful search for an instrument to measure self-efficacy in an NSF-funded project designed to investigate the motivational effects of a multi-user virtual environment (MUVE) on the science achievement of middle-school students. However, individual sections of the new instrument can contribute in general to the more-finely discriminated measurement of self-efficacy