Purpose: This research aims to determine the influence of consumer behaviour and interests on purchasing decisions for used clothing in Lubuk Pakam City. Design/Method/Approach: This research method is quantitative and associative. The type of data in this research is primary data. The data source was obtained from consumers through distributing questionnaires to consumers purchasing used clothing in Lubuk Pakam, who will be used as samples in the research. The population in this study was 93,064 people. The sample in this study was taken using a probability sampling technique using the Slovin formula, with a sample size of as many as 100 respondents. The data analysis used is multiple linear regressions. Findings: The results show that consumer behaviour has a positive and significant effect on purchasing decisions, indicating that purchasing second-hand clothing is primarily motivated by price considerations, product quality, and trend-following behaviour. Conversely, consumer interest does not significantly affect purchasing decisions, suggesting that although consumers may be attracted to second-hand clothing, it does not automatically translate into actual purchases, likely due to social stigma or hygiene concerns. Simultaneously, consumer behaviour and interest together significantly influence purchasing decisions, confirming that decision-making in this market is multifactorial and cannot rely solely on interest alone. Originality/Values: These findings contribute theoretically by enhancing the understanding of consumer behaviour in second-hand clothing purchases and offer direct practical implementations. For business actors, the insights enable the design of more targeted marketing strategies that emphasise consumer behaviour factors such as price sensitivity, brand perception, and trend adoption, rather than solely relying on consumer interest. For policymakers, the results support the development of more balanced regulations that protect public health and promote local industries while accommodating the strong consumer demand for second-hand clothing. Additionally, the findings help advocate for programs that ensure hygiene standards and legal compliance in the second-hand clothing trade in cities like Lubuk Pakam.