Global challenges such as climate change, increasing urbanization and a lack of transparency of food chains, have led to the development of innovative urban food production approaches, such as rooftop greenhouses, vertical farms, indoor farms, aquaponics as well as production sites for edible insects or micro-algae. Those approaches are still at an early stage of development and partly unknown among the public. The aim of our study was to identify the perception of sustainability, social acceptability and ethical aspects of these new approaches and products in urban food production. We conducted 19 qualitative expert interviews and applied qualitative content analysis. Our results revealed that major perceived benefits are educational effects, revaluation of city districts, efficient resource use, exploitation of new protein sources or strengthening of local economies. Major perceived conflicts concern negative side-effects, legal constraints or high investment costs. The extracted acceptance factors deal significantly with the "unknown". A lack of understanding of the new approaches, uncertainty about their benefits, concerns about health risks, a lack of familiarity with the food products, and ethical doubts about animal welfare represent possible barriers. We conclude that adaptation of the unsuitable regulatory framework, which discourages investors, is an important first step to foster dissemination of the urban food production approaches.