The EU Green Deal sets challenging goals for cities, including a 90% reduction in Green House Gas (GHG) emissions from transport by 2050. This requires an integrated and coordinated approach to urban mobility planning, represented by Sustainable Urban Mobility Plans (SUMPs), and encouraged by European legislation. However, the experience of cities with SUMPs varies substantially among the EU Member States. Using qualitative and quantitative methods of data analysis, this paper aims to explore the institutional settings, practices, and barriers to sustainable mobility in Czech cities and differences between cities with and without a SUMP. The data were collected using interviews and an online questionnaire survey among stakeholders who substantially influence the urban planning praxis. The data reveal that monitoring, evaluation, and public involvement are underestimated by analyzed cities and the perception of a need for a significant transport behavior change is still quite low among local politicians. A SUMP brings substantial benefits to Czech cities of all sizes, even in the initial phase of its implementation. The cities that have developed a SUMP apply various sustainable transport measures more often, create more participation activities, and are better at evaluation than cities without a SUMP.