In a commitment to raising the knowledge, skills, and opportunity of its citizens, New York State seeks to enhance students’ cognitive, social, emotional and academic achievement throughout its schools. Given that research indicates that teacher quality is the single most powerful influence on student achievement, it is essential to ensure that teachers are provided with ongoing, high quality professional development to sustain and enhance their practice. Indeed, teacher professional development is an essential element of comprehensive school improvement. The professional development needs of other members of the school community, including administrators and support personnel, must also be addressed to ensure a focus on continuous learning and to create the conditions necessary for closing the achievement gap and improving the achievement of all students. These standards provide guidance for achieving high quality professional development planning, design, delivery and assessment, and should serve as a foundation for all professional development in our schools.