The purposes of this study were: 1) to develop additional curriculum in the Career and Technology Learning Strand for Mathayomsueksa 2 ; 2) to comprehend the efficiency and effectiveness of the additional curriculum developed. The samples of the study consisted of 20 parents or guardians of Mathayomsueksa 2, 5 teachers of the Career and Technology Learning Strand, and 40 Mathayomsueksa 2 of Rachaprachanukroh 16 School obtained by using the purposive sampling technique. Research instruments were as follows: 1) interview protocol consisting of 13 issues used to explore problems and needs ; 2) questionnaire with 10 items ; 3) 8 lesson plans as implementing the developed additional curriculum ; 4) 40-items of achievement test with discriminating power (rxy) ranging from 0.49 to 0.75 and the reliability (α)) of 0.91. The statistics used to analyze data were percentage, mean, standard deviation and t-test (Dependent samples). Findings were as follows: 1. Fundamental data revealed that the involved persons realized that the additionalcurriculum was important and required to develop. Their opinions were at 90 percent of consensus.The components of the additional curriculum developedwere found, as evaluatedby the experts, to be appropriate and consistent with thelocal contexts. The curriculum met this criterion at 4.80 of means. The opropriateness of lesson plans was at 4.67 of means. 2. From conducting try-out activities, it revealed that: 2.1) The efficiency of the additional curriculum developed was 82.69 / 84.69.This was higher than the established criterion. 2.2) The effectiveness index of the lesson plans was 0.7100. 2.3) For learning achievement, the students’ post-test score was significantly higher than pre-test score at the .01 level of significance. 2.4) The students had process skills at the level of 4.63 Ofmeans. 2.5) The students’ satisfaction toward learning based on Thecurriculum developed was at the highest level of 4.67 of means. In summary, the development of additional curriculum in the Career and TechnologyLearning Strand on the topic of Designing Products from Local Textiles for Mathayomsueksa 2was consistent with local problems / need and contexts. It promoted students-centered learning approach. It also provided various learning activities and materials. For thesereasons, the students were successful intheir learning.