Sustainability is the use of existing resources in an economy without excessive destruction, considering the welfare of future generations. The reflection of sustainability, a concept that concerns every field in finance, has been in the form of fiscal sustainability. Fiscal sustainability is associated with the state’s ability to pay and is explained through budget deficits and public debt burden indicators. This study determines whether fiscal sustainability exists in Türkiye between 2000 and 2023throughtheNonlinear BoundsTest(NARDL).TheNARDLmethodconsiders the asymmetric effects of the variables included in the model. Accordingly, fiscal sustainability in Türkiye was investigated using two separate models created in the study, considering the positive and negative effects of the variables. When the f indingsobtainedwereevaluated,itwasconcludedthattherewasfiscalsustainability in Türkiye in the period examined. However, the degree of fiscal sustainability was weak in both created models. It was concluded that decreased public expenditures increased public revenues in the long term while reducing public debts increased the budgetbalance.Inaddition, it hasbeenconcludedthattheincreasesanddecreasesin public expenditures, among the variables used in determining fiscal sustainability, have asymmetric effects on public revenues. In this context, taking the existing sustainability into a stronger form by considering its asymmetric effects is crucial for the stability of fiscal policies.