For the past several years, Marguerite Roza has led a series of Center on Reinventing Public Education studies on how school districts spend their money. Her reports have shown that school districts often do not know how their funds are allocated, and that common district practices often lead to lower spending in low-income neighborhood schools. Those practices include seniority-based allocation of teachers, which allows the highest-paid teachers to cluster in schools serving well-off students; salary cost averaging, which hides the spending inequalities caused by teacher placement; and distribution of central office services, which can favor schools with stable leadership and demanding or active parent groups. This is the first in a series of working papers on ways people working for the disadvantaged might use evidence about within-district spending inequalities. It examines legal bases for complaints against unequal spending, including the education and equal protection clauses of state constitutions and, in some cases, the 14th Amendment of the U.S. Constitution.