Schools are required to provide multilingual learners (also referred to as English learners) with specialized instruction, per federal and state laws and regulations. However, service delivery options vary from state to state and from school to school based on policies, mandates, demographics, and a range of other variables. In recent years, more and more schools are using collaborative integrated services and co-teaching to meet the needs of these learners. This guide is presented as a quick reference for K-12 English Language Development (ELD) teachers and their general education colleagues, as well as coaches and administrators. It is designed to support all educators as they engage in a complete collaborative instructional cycle consisting of co-planning, co-teaching, co-assessing, and reflecting on practice.