Educators at Rabun County High School in northeast Georgia identified improved student proficiency in critical thinking as a major school goal. In order to infuse thinking skills instruction across the curriculum, a nine-member interdisciplinary team of teachers worked closely with an invited learning specialist for one year. Collaboration resulted in the evolution of a new model for the infusion of critical thinking skills across the curriculum-the CRTA Model. This paper describes the CRTA Model for School Improvement in Critical Thinking, a comprehensive approach that involves four steps: 1) Create the right climate; 2) Reflect/Revise instructional objectives; 3) Teach thinking skills and dispositions explicitly; and 4) Assess critical thinking for real-life use.