Networks appear to be vital living organisms which change, grow and develop through time; hence networks are shaped, dissolved and reformed on a constant base. Although an extensive body of research has focused on the outcomes and the antecedents of the interorganizational networks formation, less attention has been paid to understand why and how these networks evolve through time, especially in the context of small-medium sized firms. This thesis aims to address this research gap and to broaden the field of the SMEs’ inter – organizational network development by considering the perceived environmental uncertainty (PEU) as an exogenous, deriving from outside the network, triggering factor. In that respect, this thesis explores if and how the three types of PEU, stemming from several domains of the external environment may trigger the development of networks in terms of their structural and interactional dimensions. To achieve this aim, a single – embedded case study of Greek tourism industry, applying the philosophical prism of critical realism, has been undertaken to seek causal explanations in the relationship between PEU and the SMEs’ network development. The findings demonstrated that PEU, particularly state and to a lesser extent response PEU, prompted the SMEs to develop their networks in several ways related to their structure, the strength of the relationships and the exchanging content among partners.