Experiential learning theory places experience at the center of learning. Kolb's four-stage cycle of experiential learning suggests that effective learners must engage fully in each stage of the cycle--feeling, reflection, thinking, and action. This research assesses the alignment of Kolb's experiential learning cycle with the week-long Summer Institute of "Assisting, Collaborating, and Training ESL Secondary Content Teachers" (ACT-ESL), the first stage of a professional development model designed to train content teachers of English Language Learners (ELLs). Qualitative and quantitative data analysis from pre- and post-surveys determined positive changes in participants' understanding of key ELL concepts, knowledge, and understanding of instructional strategies and practices. Analysis indicated that the Summer Institute had a large effect (d > 2.00 for each scale), regardless of previous training in ELL instructional strategies. Findings show that the Summer Institute incorporated the cycle of learning and tenets of Kolb's experiential learning theory and evidenced teacher learning.