ABSTRACT Abdullah 2015. Improving Students’ Speaking through Group Work Activities (A Classroom Action Research at SMAN 2 Sigli). Thesis, Graduate Program in English Language Education of Syiah Kuala University, Darussalam, Banda Aceh. Advisors: (1) Dr. Usman Kasim, M. Ed (2) Abdul Manan, M. Sc., M. A., Ph. D Key words: Improving, Speaking and Group Work This study was conducted at SMAN 2 Sigli to improve the students’ speaking skill in English through Group Work Activities. The group work was implemented to the third year students of XII-IPA1 through a Classroom Action Research. The study was based on the researcher’s preliminary study finding that the causes of problems related to the students’ disability to speak English are: 1) The teacher still uses conventional method in teaching speaking; 2) Only 25% of Students’ English Proficiency meet the speaking target test or Minimal Grade Criteria-Kriteria Ketuntasan Minimal (KKM) which is 75; 3) The students are bored and loose their interest to speak; 4) They are shy and reluctant to speak, and 5) They are lack of practice. The study was done in three cycles by following the procedures of action research, namely: Planning an action, implementing the plan, observing the action, and reflecting. It aims at improving the teacher’s performance in implementing the group work activities in teaching speaking, finding out the effectiveness of the group work activities in improving students’ speaking skill, knowing the students’ responses toward the implementation of the group work activities in speaking class. To collect the data, some instruments such as observation sheet, test and questionnaire were used. The obtained data were presented in two ways, qualitative and quantitative data procedures. The qualitative collected data were analyzed by using qualitative data procedure while quantitative data analyzed by using statistical method in the process of implementing analysis scoring rubric for speaking assessment, it is the total score of the students divided the total number of students. The finding of this research shows that group work activities were effective to improve the students’ ability in speaking and the teacher’s performance in teaching as well. The result of pre-test was the highest score is 80 and the lowest one is 60 while the result of post-test in the third cycle the highest score is 95 and the lowest one is 70. This means that most of the students got much improvement in speaking. It could also be seen based on the result of observation for teacher, from 62% increased to 75% and 86% and for students from 56% increased to 72% and 85% from the first cycle into second and third cycle. The result of the research also indicates that the students had good responses toward the implementation of the group work activities.