PurposeThis study aims to explore how the fact of belonging to clusters of dissimilar form or characteristics modify the application of human resource management (HRM) practices, as well as those knowledge-sharing processes that guide and encourage the intrapreneurial behavior of employees (IPB) in firms belonging to the cluster. The main thesis is that the application of HRM practices and some knowledge management processes are strongly conditioned by the form or characteristics of the cluster, all this in a knowledge-intensive context that requires a contingent application of such practices.Design/methodology/approachThe research strategy chosen was a qualitative case study, given that the insight the authors were seeking could only be obtained through a fine-grained analysis inside the firm where it is very difficult to decouple the phenomenon to be observed from the context where it takes place. Two cases were selected to analyze the phenomenon in-depth and compare their results; they were big and technologically advanced firms but belonging to clusters of different forms and characteristics.FindingsResults show that the influence of the cluster based on location is greater than the effects of the cluster formed by networks, where globalization and external ties play an important role. HRM practices and knowledge sharing processes that lead to intrapreneurial behavior are conditioned, only in part, by the characteristics of the cluster. Particularly, the geographical cluster encourages knowledge sharing with competitors and customers, mainly for technical training processes and because of belonging to a sectoral association. However, HRM practices, with the exception of training and compensation policies, are mainly conditioned by the company's culture and internal factors, rather than by belonging to a specific cluster.Practical implicationsFirms belonging to an organized cluster should encourage the development of practical training-oriented programs, not only on technical aspects but also on other skill and competence-based areas. In addition, training based on strategic issues both for top and middle managers could be an interesting initiative. Additionally, clustered firms should develop more knowledge-retention policies to limit the degree of rivalry in the sector, as it is very common for a firm to search for new and specialized talent in the rest of competing firms in the cluster.Social implicationsConsidering the economic impact of the geographical cluster, its effect on the employment and development of a region and taking into account the relevant and dynamic role of research institutions and associations, policymakers should support and facilitate the activity of those institutions, reinforcing the relevance of industrial districts or geographical clusters that are threatened by the pressures of globalization.Originality/valueThis study brings new insight into the effect of the form and characteristics of the cluster on HRM practices and knowledge sharing processes that lead to intrapreneurial behavior. The study may open the field for additional studies that, from a qualitative and quantitative perspective, analyze this topic in depth. The paper shows that IPB depends not only on the support of the institutions created in the cluster but also on the culture and competitive strategy of the company. Belonging to a geographical cluster can have an influence on firms’ behavior and can, through the trust generated among its members, facilitate knowledge-sharing processes and intrapreneurial behavior.