Online shops are an indispensable part of the economy, and knowing customer expectations is the key to success in e-commerce. The aim of this article is to identify the key determinants of the quality of online shop functioning from the perspective of Generation Z in Poland. The paper presents the results of a literature review and a survey conducted among representatives of this generation. The results indicate that the quality of online stores is determined to the greatest extent by: the quality of the product, including the raw material/material from which it is made, the price of the product, the competence of employees and their professional approach to work, personal data protection and a trusted payment system, SSL certificates, and product warranty. Understanding the expectations of Generation Z is key to success in the rapidly growing e-commerce market.