This study aims to reveal factors that impact the logistics service performance of sellers in online marketplaces. The convenience of online shopping is changing the shopping habits and steering consumers towards online channels. This situation compels retailing firms to be visible online. However, unlike big retailing firms, smaller firms (especially SMEs) find it very difficult to sell their products on their proprietary websites due to high marketing, technical, and marketing costs. For this reason, many of them choose to sell their products in online marketplaces, but price-based competition among sellers in these marketplaces increases the importance of logistics service performance for competitiveness. Therefore, there is a need to reveal factors that impact the sellers’ logistics service performance in online marketplaces. To this end, this study examines the sellers on a Turkish online shopping site GittiGidiyor, using a multi-group structural equational modelling. As a result of this examination, the factors found to affect logistics service performance are as follows: i) the number of different product categories offered by sellers, ii) selling items within particular product categories, iii) the 3PL company choice, iv) free shipping policy, v) the city from which products are shipped. These findings provide both theoretical and managerial insights. They not only enhance the understanding on the determinants of logistics service quality in an online marketplace context, but also provide guidance to e-tailers in elevating their logistics service performance in online marketplaces.