The authors examine how the collective bargaining agreement (CBA) negotiated between teachers' unions and districts is associated with schools' and districts' performance under accountability pressures in California. They find that CBA restrictiveness is associated with the increased likelihood that districts will be in Program Improvement (PI) and at higher levels of PI, and with lower school- and district-level proficiency and graduation rates. They also show that strong contract schools and districts that have higher proportions of minority, low-income, and low-achieving student are even less likely to meet performance targets and have even lower proficiency rates. (Contains 4 notes and 5 tables.)