Most European states have ratified the UN Convention on the Rights of Persons with Disabilities (CRPD), but implementation varies at national and local levels with municipalities often playing a key role. Decentralization policies have often led to municipalities providing social support as well, but little attention has been paid to the accessibility of municipal support for persons with disabilities in the light of the CRPD. Therefore, this article presents the Dutch 2015 Social Support Act (SSA) as a case study. The SSA introduces the right to an assessment. This legal evaluation moment has far-reaching consequences for persons with disabilities as it serves as the gateway for access to reasonable accommodations under the CRPD. Dutch municipal councils implement their assessment systems in different ways, but social district teams are usually set up to execute the assessment under the mandate of the municipality. It is often the case that social workers fulfil both counselling and gatekeeping roles, despite the fact that they are not necessarily trained to combine these dual responsibilities. This article identifies impeding factors that influence the gaining of access to municipal social support at the level of the social system, the involved organizations and the individual professionals. It takes a legal-anthropological approach based on in-depth multidisciplinary interviews with experts in the field of disability rights advocacy, social policy and human rights, or with experiential expertise. The results indicate a lack of alignment between the SSA and the CRPD. The discussion gives recommendations for a broader implementation of the CRPD.