United States education has experienced a big push for students to learn coding as part of computer science and more explicitly address computational thinking (CT). However, CT remains a challenging subject for many students, including pre-service teachers. CT, which overlaps mathematics and computer science, tends to be offered as an elective course, at best, in P-16 education. Pre-service teaching profession students usually do not have foundational knowledge to guide them in integrating computational thinking into the curriculum that they will eventually teach as instructors themselves. This chapter explains computational thinking in light of K-8 education, discusses issues and needs in integrating CT into K-8 curriculum, identifies relevant theories and models for teaching CT, describes current practice for integrating computational thinking into K-8 curriculum, and discusses pre-service teachers' preparation that can lead to their successful incorporation of CT into the curriculum.