This paper investigates sustainability principles in the city of Curitiba, in Brazil, as a pioneer which has commenced its sustainability journey since the 1960s. Analyzing sustainability principles in Curitiba, the paper aims to study their applicability in the case of Shiraz in Iran. Considering the complexity of physical, social, cultural and environmental systems in urban planning, the research underlines the vitality of contextual studies, integration and implementation strategies in sustainability achievement in urban scale. It shows how and to what extent sustainability principles in a city can be adapted to other contexts. This comparative study benefits from interpretive methods of data collection and analysis based on primary and secondary resources. A theoretical framework of planning based on equity, economy and ecology is being utilized in data collection and analysis. The investigation indicates that Curitiba’s sustainability agenda is based on a set of integration and implementation strategies which combine decision making, education, transportation, public welfare, heritage conservation and waste management. It is argued that although every urban environment has its specific opportunities and constraints, still there are many things to learn from others.