Participation in the federally-subsidized school breakfast program often falls well below its lunchtime counterpart. To increase take-up, many districts have implemented Breakfast in the Classroom (BIC), offering breakfast directly to students at the start of the school day. Beyond increasing participation, advocates claim BIC improves academic performance, attendance, and engagement. Others caution BIC has deleterious effects on child weight. We use the implementation of BIC in NYC to estimate its impact on meals program participation, BMI, achievement, and attendance. While we find large effects on participation, our findings provide no evidence of hoped-for gains in academic performance, nor of feared increases in obesity. The policy case for BIC will depend upon reductions in hunger and food insecurity for disadvantaged children, or its longer-term effects. The following are appended: (1) Mean Annual Breakfast and Lunch Participation Rates: Balanced Panel of Elementary and Middle School; (2) Impact of BIC adoption on meals program participation, 2001-2012--models using school specific linear time trends; (3) Impact of BIC on obesity and BMI--using grade-specific BIC treatment; (4) Impact of BIC on ELA and math achievement--using grade-specific BIC treatment; (5) Impact of BIC on obesity and BMI--using percent of BIC classrooms treatment; and (6) Impact of BIC on ELA and math achievement--using percent of BIC classrooms treatment.