Quality assessment systems have recently expanded, serving as indicators for the assessment and ranking of higher education institutions worldwide. The growing development of new educational methodologies, like Blended Learning, requires the design and validation of tools that allow for their assessment. The objective of this article is to describe the process of statistically validating a tool designed to assess the educational quality of Blended Learning courses. This paper presents a systematic conceptualization of the educational quality in Blended Learning systems and provides a reliable and valid tool for quality assessment of the design and implementation of combined learning methodologies.