Over the last two decades, there has been a significant surge in the self-employment rate among Hispanics, especially among Hispanic immigrants. However, the reasons behind this increase remain underexplored. This paper addresses this gap by examining the role of undocumented immigrants, a substantial part of the Hispanic immigrant population, by discerning immigrants’ legal status in the Current Population Survey–Annual Social and Economic data (1994–2018). The findings reveal that the nearly doubled self-employment rate among Hispanic immigrants is primarily driven by undocumented individuals, especially those of Mexican origin. A key factor is the post-9/11 tightening of immigration enforcement, which worsened job prospects for undocumented immigrants, pushing many into self-employment. This event triggered a distinct pattern in Hispanic self-employment, setting it apart from other demographic groups. Other factors, such as business cycles, state-level immigration policies, the gig economy, and the growth of the Hispanic community, also contribute but play a lesser role.