Wicked problem refers to a situation with general agreement that change is needed, but with no apparent solutions. Housing affordability, energy poverty, air travel, GDP as a measure of economic prosperity, urban sprawl, landfilling municipal solid waste, fossil fuel and economic growth are wicked problems in most countries. Wicked problems are often neglected in preference for seeking solutions that do not change the unsustainable situation, but rather by making incremental improvements. Transition Engineering research has identified three key reasons why wicked problems defy solutions. Firstly, scientists focus on the harms to people and nature. Warnings of doom take up much of the attention and it is believed that becoming aware is an action. Secondly, the incumbent system resists change, as it is profitable, operating, and a sunk cost. Thirdly, wicked problems are overwhelming, and stifle creative problem solving. The Transition Engineering Wicked Problem Investigation works through a series of discussions focused on a specific place and human need, while considering whole systems and stakeholders. The outcome is the actionable definition of an underlying core issue causing the wicked problem, thus creating the possibility for engineering the transition through net positive initiatives and shift projects. This paper presents the practice-derived Wicked Problem Investigation method and a use case of an investigation workshop with stakeholders. The results show that the Wicked Problem Investigation method can be picked up by transdisciplinary engineers working on engineering the transitions of socio-technological systems, and that stakeholders with wicked problems gain actionable expression of problems.