Participation in the federally-subsidized school breakfast program (SBP) often falls well below that of the lunch program. In NYC, for example, less than one third of all students eat a school breakfast each day, even though it is provided free to all students and roughly 3 in 4 students are poor. To increase participation, many schools have adopted Breakfast in the Classroom (BIC), serving breakfast direct to students in class at the start of the school day. Breakfast consumption has been found to improve child cognitive performance, and two recent studies have found a positive effect of BIC on achievement. Its impact on obesity, however, is unknown. In this paper, we exploit the staggered introduction of BIC in NYC to estimate its impact on meal participation, obesity, BMI, academic performance, attendance, and perceptions of the school environment. We find little evidence that BIC increased obesity, and some evidence it reduced it, particularly among middle school girls. There are mostly positive effects of BIC on achievement, with the largest effects for boys. These effects are, however, much smaller than those found in previous studies. We find consistently positive, but small, effects of BIC on attendance rates.