<p>Consumers are slowly turning to sustainable fashion, but major constraints that prevent and reduce the adoption and purchase of sustainable fashion are not completely known. In this context, the purpose of this study is the proposal and validation of a measurement scale to assess the factors that prevent consumers from purchasing sustainable fashion, focusing on online second-hand fashion clothing. Aligned with this purpose, the measurement invariance of the scale for second-hand fashion purchase frequency is analyzed. Construct validity is examined through Exploratory Factor Analysis (EFA), followed by Confirmatory Factor Analysis (CFA), and measurement invariance analysis on a sample of 512 consumers. Results confirm the validity of the measurement scale, comprising seven factors, namely sanitary/hygienic condition, purchase uncertainty, low product reliability, embarrassment, low product quality, poor fashionability and distrust towards the online store. Similarly, measurement scale invariance indicates the lack of bias of purchase frequency, contributing to the generalizability of the obtained results. This study expands knowledge through the proposal and psychometric validation of a multidimensional scale on the barriers that hinder the purchase of second-hand fashion online, providing insights to better understand the low rates of purchase of sustainable second-hand fashion products through the internet.</p>