The increase in the unevenness of indicators of regional socio-economic development in Ukraine is causing changes in regional economic security, in addition to the deterioration of national welfare. Therefore, there is a need to develop new theoretical and practical approaches for assessing such disparities and forecasting their dynamics. In this article, a toolkit for modelling crises and catastrophes in disparities of regional development is presented, using the example of Ukraine. The purpose of this study is to create models that assess the crisis dynamics in regional disparities in Ukraine, in order to develop tools for ensuring economic security in the region. To achieve this purpose, the following tasks have been identified: to evaluate convergent-divergent processes and the long-term interaction of regional disparity indicators; to simulate possible crises and catastrophes in various spheres of socio-economic development of regions according to the levels of their disparities; and to demonstrate the mutual dependence between disparities of the regions and levels of their economic security. The result of the crisis dynamic assessment is a set of predictive models of possible catastrophes that may occur in Ukraine's regions. This allows for obtaining reliable results for the qualitative analysis of stability factors of disparities in the socio-economic system, accounting for different time intervals that determine the peculiarities of the country's development. The array of constructed models is an effective tool for researching crisis processes in the dynamics of disparity indicators, as they allow for identifying and more thoroughly investigating non-linear cyclical processes in regional economic development, as well as predicting changes in levels of economic security. Such a toolkit allows for the development of a strategy for balanced regional and country development, and for ensuring regional economic security.