This report draws on a statewide survey to examine how learning time is distributed across California high schools. The survey, conducted by UCLA IDEA during the 2013-2014 school year, included a representative sample of nearly 800 teachers. Survey findings highlight inequalities in the amount of time available for learning across low and high poverty High Schools. Community stressors and chronic problems with school conditions lead to far higher levels of lost instructional time in high poverty high schools. The study methodology is appended. [For the executive summary, see ED574619.]