The extent of environmental degradation is increasing and environmental protection requires utilizing the cultural and social capabilities of human communities. The purpose of this study was to investigate the environmental citizenship of residents aged 18 and older in Shiraz and its relationship with social capital and socio-economic variables. The method of this research was a survey and the required information has been collected using a questionnaire. The study sample is 1045 residents of Shiraz who were selected using the Cluster Sampling Method. To evaluate the validity of the questionnaire, factor analysis was used, and to determine its reliability, the internal coordination of the instrument was used by Cronbach's Alpha Method. The results show that the variables of social capital, socio-economic status,  had a positive and significant relationship at the level of 99% with the environmental citizenship variable. There is a significant difference between the environmental citizenship status of the respondents according to their marital status. Married people have stronger environmental citizenship than others. In total, the independent variables explained 15.3% of the changes in the dependent variable of environmental citizenship. Environmental citizenship and social capital are synergistic. Strengthening social capital and its elements is important for strengthening environmental citizenship.