Considering complexity of subsea production systems, interactions among components are often characterized by failure dependences that may accelerate their degradation. Besides, not all components share the same failure dependences due to system design and functional interactions. Such heterogeneous failure dependences further complicate maintenance strategies and activities in the dependent multi-component subsea production systems. This chapter introduces a comprehensive approach to assess heterogeneous failure dependences and a maintenance optimization model using Markov processes tailored for multi-component systems. The method is demonstrated through a practical example of the subsea transmission system, highlighting the impact of heterogeneous failure dependences. The results indicate that the proposed framework and model can optimize maintenance strategies, enhancing system availability while reducing maintenance costs.