Although possible asymmetries for univariate and multivariate dynamics have been the focus of interest in many areas of economic explorations, it seems that most of the research on military expenditure - economic growth nexus has tended to assume linear relationships. This paper aims to examine possible nonlinearities in military expenditure-economic growth nexus employing data for a sample of 103 countries covering the 1988-2019 period. For this purpose, Panel Smooth Transition Regression, PSTR, models are estimated not only for all countries' sample but also for low income, middle income, and high-income countries' subsamples to reveal possible distinct asymmetric relationships for country groups with different income levels. Empirical results for the whole sample, low income and middle income groups indicate that military expenditure not only governs the regime change, but also low and high levels of military expenditure have distinctive and rising negative effects on economic growth with dissimilar threshold effects. Moreover, empirical findings also indicate that net arms exports govern regime change for high income countries, and as net arms exports rise, the negative impacts of military expenditure on economic growth become deeper.