We use the 2014 and 2018 panels of the Survey of Income and Program Participation to create a schema of earnings that come from employee and nonemployee sources. Traditional earnings are from a job or incorporated business, while nontraditional earnings are from an unincorporated business or other work arrangement. We then create a typology of workers based on their experience with traditional and nontraditional earnings, describe workers of each type along dimensions of demographics, financial well-being, and beneficiary status, and use regressions to identify key predictors of earnings sources. Among prime-age workers, we find that workers with nontraditional earnings vary significantly based on whether the nontraditional earnings were the only source of wage income or in conjunction with traditional earnings. Among older workers, we find that receipt of Social Security benefits is a key predictor of nontraditional earnings. We discuss both findings and their research and policy implications.