Ambient intelligent systems are context aware by perceiving and reasoning about their environment, they perceive the needs of their users and proactively respond to these needs by being context sensitive. Users do not interact with these systems by traditional means only, but also through behavioural interfaces. This combination of mixed initiative systems and unconventional interfaces puts strong requirements on the explanatory capabilities of any system. The work presented here focuses on explaining the behaviour of an ambient intelligent systems to its users. It demonstrates how explanations can be combined with context to deal with the different types of explanations that are required for a meaningful interaction of a system and its users.