Eligibility for government services is described in legislation that is complex and subject to frequent change. The legislation must be reflected in government information systems that are themselves complicated and dynamic. When applying for a government service, a person must interact with a government user interface (GovUI), such as an online form and provide the government with the information to assess the applicant’s eligibility for a service. This study uses the GovUI as a representation of the data being used by the government to determine the eligibility of an applicant. The research investigates the problem of alignment of GovUI to legislation. The research problem is addressed by the research question ‘Can an ontologically based method be developed that is useful/effective in investigating alignment between legislation and government user interfaces?’ Where misalignment is found, the supplementary research question can then be asked ‘What degree of misalignment is revealed by using the GovUI-Onto method?’ In information systems (IS) research, an ontology represents a shared understanding about a domain through the concepts used, and the relationships between the concepts. This research develops an ontological method comparing a set of three, of many, ontological components from the legislation and the GovUI to determine if there is alignment, or misalignment. A misalignment between the GovUI and the legislation may have consequences for a determination for eligibility. In a welfare setting, these consequences may mean that applicants for welfare have increased difficulty in accessing benefits for which they are entitled. Creating what is in effect further hardship for some of the most vulnerable people in our society. In this research, Design Science Research (DSR) methodology is used to build and evaluate an artefact that can be used to investigate alignment of the GovUI to the legislation. The artefact is the GovUI-Onto method. The GovUI-Onto method is evaluated by applying the concept ‘Australian resident’ in three research public sector settings: welfare, tax and immigration. These settings were chosen because each one implements a different legislative definition of the term Australian resident. The proposed research is relevant to theory and practice and relevant to the continuing transformation of business to digital. Theoretically, it exapts an ontologically based method from known ontology building and ontology mediation theories to solve a significant alignment issue in the government domain. In practice, the research uses examples from legislation and GUI that can be extended more broadly to facilitate greater alignment in public sector settings. This research demonstrates how a representation of the legislation and GovUI can be detected using an ontologically based method in a non-semantic way. Future work may investigate an extension of the method in an automated solution to include the semantics. In addition, future work may also apply GovUI-Onto to the investigation of other key definitions used in the public sector such as child, citizen, partner, employer, employee, and service.