This study examines the effects of the MATC Promise, a public-private partnership that offered to pay tuition at Milwaukee Area Technical College (MATC) for local high school graduates. The MATC Promise exemplifies the most common type of college promise program, a last-dollar community college tuition promise. If students completed academic milestones, applied for state and federal aid, and qualified based on low family income, then the Promise would cover any remaining tuition charges. In practice, the message of a promise was the main treatment, since most eligible students would not have any tuition charges remaining for the program to cover after applying state and federal aid. We evaluate the effects of the Promise on increasing college enrollment and degree completion after its introduction in 2016. Milwaukee is unique within the Wisconsin, making it difficult to find relevant comparison groups in statewide data. Examining the interrupted time series within the city’s school districts shows an increase in enrollment at MATC from 10 percent of high school graduates to 15 percent after the Promise was introduced. About half of the increase came from students who would not have enrolled at all, with the rest diverting from enrolling at other colleges and universities. These effects were concentrated among lower-income students and those in the inner city. These results indicate that the Promise positively influenced college attainment by encouraging students to access state and federal aid they already qualified for. We conclude that the message of college affordability was effective at encouraging students to overcome application barriers and enroll in college.