We study how human capital diversification, in the form of double majoring, affects the response of earnings to labor market shocks. Double majors experience substantial protection against earnings shocks, of 56%. This finding holds across different model specifications and data sets. Furthermore, the protection double majors experience is more pronounced when the two majors are more distantly related, highlighting the importance of diverse skill sets. Additional analyses demonstrate that double majors are more likely to work in jobs that require a diverse set of skills and knowledge and are less likely to work in occupations that are closely related to their majors.