Context: As the adoption of continuous delivery practices increases in software organizations, different scenarios struggle to make it scales for their products in long-term evolution. This study looks at the concrete software architecture as a relevant factor for successfully achieving continuous delivery goals. Objective: This study aims to understand how the design of software architectures impacts the continuous deployment of their software product. Method: We conducted a systematic literature review to identify proper evidence regarding the research objective. We analyzed the selected sources adopting a synthesis and analysis approach based on Grounded Theory. Results: We selected 14 primary sources. Through our analysis process, we developed a theory that explains the phenomenon of Architecting for Continuous Deployment. The theory describes three other phenomena that support Architecting for Continuous Deployment: Supporting Operations, Continuous Evolution, and Improving Deployability. Furthermore, the theory comprises the following elements: contexts, actions and interactions, quality attributes, principles, and effects. We instantiated these elements and identified their interrelationships. The theory is supported by providing bi-directional traceability from the selected sources to the elements and vice-versa. Conclusions: Developing adequate architecture plays a crucial role in enabling continuous delivery. Supporting operations becomes vital to increase the deployability and monitorability of software architecture. These two outcomes require that developers accept responsibility for maintaining the operations. The continuous evolution of the architecture is essential, but it must consider balanced management of technical debt. Finally, improving deployability requires attention to the test strategy and how it affects downtime to enable efficient pipelines.