The aim of the research is to find out: (1) whether there is a significant difference in writing skill between students taught by using Think-Talk-write technique and those taught by using Guided Writing technique; and (2) whether Think Talk Write technique is more effective to teach writing than Guided Writing technique. The research method used in this study is a quasi-experimental research. The research was conducted at SMP N 1 Kaliori in the academic year 2015/2016. The population of the research is the seventh grade of SMP N 1 Kaliori. The samples are class VII.2 as the experimental class which consists of 34 students and VII .1 as the control class which consists of 34 students. The research instrument used to collect the data in this study is test. The data were analyzed by using t-test formula. The computation of the data shows that the t-observation (to) is 4,286 which is higher than t-table (66, 0,05) = 1.997. Therefore, it can be concluded that there is a significant difference in writing skill between the students taught by using Think Talk Write technique and those taught by using Guided Writing technique. The mean of the group of students who are taught using Think Talk Write technique is 73.38 while those are taught using Guided Writing technique is 66.82. Therefore, it can be concluded that Think Talk Write technique is more effective to teach writing than Guided Writing technique.