By gliding sustainability into the mainstream areas of marketing strategy, the purpose of the current research is to analyze the influence of the entrepreneurs' orientation towards sustainability on relational marketing practices-i.e., interaction versus network marketing. Placed within a comparative setup, the investigation included a sample of 104 business owners of Romanian small and medium-sized enterprises (SMEs) from the services sector, the selection of participants being subject to well-defined pre-established criteria. Acknowledging the research gap which addresses the type of business strategy fit for entrepreneurs' orientation towards sustainability, the conceptual model integrated a categorical moderator variable (Planned/Emergent Business Strategies) as indicative of the potential heterogeneity among the hypothesized relationships. Both measurement and structural models were appraised by means of a structural equation modeling technique, respectively, component-based partial least squares (PLS-SEM). As the findings concluded, the entrepreneurs' orientation towards sustainability accounts for almost 35% of variance in interaction marketing practices and 16% of variance in network marketing practices, thus positing a higher influence on the former. Moreover, evidence was provided that the reification of the entrepreneurs' orientation towards sustainability in relational marketing practices was not significantly dependent on the type of business strategy.