In the beginning, the popularity of Internet shopping was determined by the ability to make purchases at any time; over time, attention began to be paid to other criteria that influence the assessment of the quality of functioning of e-commerce platforms. The analysis of available literature and own research enabled the identification of a total of 33 criteria grouped into seven groups: functionality, security/privacy, assurance, convenience, personalization, customer satisfaction, and behavioral intentions. Bearing in mind that MCDM methods are widely used in quality assessment processes, this article uses the AHP and Entropy method, which made it possible to carry out analyses regarding the impact of changes in one group of criteria on the others and the overall quality level of the functioning of e-commerce platforms. The obtained results indicated the completeness of criteria set identified, as all of them are relevant to assess the quality of functioning of e-commerce platforms.