PurposeThis study investigates entrepreneurial overconfidence (EOC) levels among solo entrepreneurs at the country level. Although transitions from solo to employer entrepreneur are relatively rare, the solo self-employed have become an important source of potential job creation by virtue of the sharp increase in their numbers in the past two decades. When EOC levels are too high, job creation ambitions may be unrealistic and unrealised. Unrealised ambitions and business failure can lead not only to psychological and financial costs for the individual entrepreneurs involved, but at the societal level also to wasted government resources, and increased costs for the entrepreneurial ecosystem as a whole. Therefore, it is important to know more about the entrepreneurial overconfidence levels of solo entrepreneurs in different countries and their determinants.Design/methodology/approachUsing Global Entrepreneurship Monitor data for 71 countries over the period 2013–2016, the authors construct a new measure of entrepreneurial overconfidence of solo entrepreneurs and relate this to three recently developed indicators of national culture.FindingsThe findings indicate that EOC levels are positively related to Joy (versus Duty), and negatively related to Trust (versus Distrust). Finally, no significant relationship between entrepreneurial overconfidence and Individualism is found in the study (versus Collectivism).Research limitations/implicationsGiven the lack of literature examining the relationship between EOC levels and cultural variables hypotheses were developed using the existent body of knowledge in the area, which is at the early stage of development. The hypotheses derivation has used mostly theoretical arguments relating to the link between national culture and overconfidence of entrepreneurs in general, rather than relating specifically to solo entrepreneurs. The measure of EOC uses expectations of employment growth to proxy overconfidence, but other measures of entrepreneurial success may also be explored.Practical implicationsAs the hiring of employees can be a costly process (Coad et al., 2017), it is important that entrepreneurs have realistic expectations of what it requires to hire employees. This is especially the case for solo entrepreneurs since they do not have experience of hiring their own employees. This paper addresses such issues at an aggregate level by exploring what factors explain country differences in overconfidence levels of solo entrepreneurs.Social implicationsIt is worthwhile to distinguish between solo and employer entrepreneurs when studying their EOC levels, as the ambitions of these two types of entrepreneurs are different. Empirically, this study introduces a new measure of EOC tailored towards the solo self-employed.Originality/valueThis study contributes to entrepreneurship literature by expanding current knowledge on entrepreneurial overconfidence at the country level. Past research has studied EOC at the individual level, however limited research exists on the phenomenon of EOC from a country level perspective. This is important as unrealised entrepreneurial ambitions may not only create substantial costs for the individual entrepreneurs involved, it may also lead to substantial societal costs, including waste of government resources.