In recent years, game-based programming tools (GBPTs) such as Code.org, Lightbot, and Cargo-Bot have been developed to help children worldwide better understand programming concepts through an interesting, enjoyable and visualizable programming learning experience. However, in-service teachers' perceptions regarding the use of these game-based programming tools in K-12 instruction have received little attention. To understand the perceptions of teachers, this study integrated perceived enjoyment into the Technology Acceptance Model (TAM) to explore the factors that influence the intentions of K-12 in-service teachers to use game-based programming tools in their instructional tasks. Thirty Chinese teachers in elementary and secondary schools were invited to finish at least one hour of code tutorial at the code.org site, and then undertake a paper-and-pencil questionnaire. We applied the partial least squares structural equation modeling technique to analyze the extended TAM model. Results demonstrated that teachers' behavioral intention was determined by their attitudes toward using GBPTs. Perceived usefulness and perceived ease of use had a significant and positive influence on teachers' attitude. In addition, the results also indicated that perceived enjoyment has a significant influence on perceived usefulness and perceived ease of use, but no significant effect on the attitude of teachers regarding the use of GBPTs. [For the full proceedings, see ED621557.]