Adaptation to climate change in practice has been limited despite worldwide political attention and the availability of multiple tools to support mainstreaming. The latest IPCC reports show limited progress in adaptation, where efforts are primarily incremental, reactive and slow in responding effectively to current impacts or near-term risks. Despite the more than 380 guidelines, frameworks, tools, and methodologies available in the UNFCCC database that are designed to support climate adaptation, there remains limited evidence of their translation into practice leading to effective adaptation. The central starting point of this thesis is that there is a clear gap between theory and practice requiring urgent action, yet specific research on understanding and addressing the factors creating this gap is still lacking. This thesis aims to understand and conceptualise the theory-practice gap in climate adaptation and to identify drivers and solutions to address it. It makes a substantial contribution to the field of adaptation science and practice by laying the foundation for addressing the gap and, in doing so, improving adaptation efforts. [...]