The knowledge-based view of the firm has motivated a rich stream of research on how social factors impact knowledge acquisition by firms. More recently, information systems research has seen an increasing interest in the effect of social influences on software assimilation. This paper combines these two streams to examine the impact of social influences on software assimilation within the firm, using knowledge acquisition as a mediating variable. A structural equation model using formative constructs is developed. In this study of small and medium firms, we investigate the assimilation of three different software systems that support manufacturing. The study finds that the research model is statistically significant and provides evidence that social influences from a firm's peers, vendors, and suppliers promote knowledge acquisition and software assimilation. The study recommends a proactive role on the part of technology and enterprise intermediaries to design SME-appropriate solutions to promote software assimilation.