Movement in organisms is driven by multiple factors, foremost among them the need to acquire resources in spatially structured environments where resources are unevenly distributed. However, ecological communities are defined by the ubiquity of species interactions—ranging from competition and predation to mutualisms—which fundamentally shape the decision to move and thereby influence the evolution of motility. In species engaged in cross-feeding mutualisms (CFMs), where partners exchange benefits via the environment, the adaptive value of motility becomes especially complex. While motility can enhance resource acquisition, it also carries the risk of displacing individuals away from their mutualistic partners—regions typically rich in resources—and imposes metabolic costs associated with flagellar construction. Using a spatially explicit, mechanistic model of mutualism, we demonstrate that selection for or against motility depends on: 1) the motility status of the partner, 2) the production and uptake rates of cross-fed resources, and 3) the magnitude of motility-associated costs. We further test our simulation outcomes with experimental data from a microbial CFM involving Escherichia coli and Salmonella enterica. Our results reveal that while motility is consistently favored in S. enterica irrespective of E. coli’s motility, the selective pressure on motility in E. coli is contingent upon whether its partner is motile. This study underscores how the pervasive nature of species interactions in ecological communities plays a crucial role in shaping the evolution of bacterial motility.