Linking the knowledge-based view and the intellectual capital view of the firm, this chapter has as its purpose to underline the relevance of a specific component of intellectual capital, namely relational capital, in the knowledge acquisition and transfer processes as well as its influence on a firm’s value creation. The authors used a qualitative research based on a multiple case study, and six Spanish knowledge-intensive firms were analyzed in depth. The results show that the main relational capabilities used by firms to create value through knowledge management are: relationships with customers, suppliers and stakeholders; acquisition of established firms; setting-up of joint ventures; collaboration with Universities, national and international institutions; participation in forums and conferences; publications; advice given by consultants and experts; and benchmarking practices. These capabilities allow firms to acquire and transfer knowledge from the environment where they develop their activity with the aim of obtaining benefits such as innovations; customers, suppliers and stakeholders’ satisfaction; an improvement in the firm’s image and credibility; new knowledge; and learning.