Strategic alliances offer the possibility to combine strengths of different companies to become more successful jointly by compensating weaknesses. This technique is frequently utilized by major companies; less frequently by small and medium size enterprises (SMEs). The motivation to explore this topic more in detail is the burning question in the life of every SME. Acting globally in a competitive environment requires a certain degree of innovation to compete against major companies, which are sometimes 100 times or more, larger in revenue or number of employees. Maybe an alliance between SMEs and Large Enterprises (LEs) is exactly what will provide an avenue to growth! The aim of the master thesis is to address the following research question from the point of view of an innovative, globally acting high-tech SME: What are the reasons, circumstances and rules that make the alliances involving exactly those SMEs successful? During the research for this thesis, four strategic alliances have been explored by conducting eight expert-interviews with executives from high-tech SMEs.