Social inclusion indicators inform policy advocacy and intervention. However, a critical piece of information is often missing: public opinion. Efforts to enhance social inclusion could backfire if they provoke opinion backlash or intergroup hostilities. In this paper, we explain the importance and nuances of inclusive attitudes and develop an easy-to-use survey instrument that tracks public opinion regarding different marginalized groups and support measures systematically. Using evidence from a representative telephone survey in Hong Kong (N = 1010), as well as a parallel online survey (N = 1000), we demonstrate the multidimensional nature of public attitudes toward social inclusion and our instrument's excellent psychometric properties and potential for use in various research settings. Although developed in the context of Hong Kong, the survey items can be decomposed and adapted to suit diverse urban societies. By highlighting the importance and complexity of public opinion, we hope to foster a more participatory approach to promoting social inclusion.