Keywords: Guessing Game, Speaking Skill, Teaching The research aims at finding out if the use of Guessing Games strategy (developed by Amato R.P (1988) ) can improve students’ speaking skill. The population was all of the eighth grade students of SMP Negeri 2 Lhokseumawe. The sample was the students of class VIII-1 which consisted of 31 students. The researcher used simple random sampling to choose the sample. She conducted pre-test, treatment, and post-test to collect data. Based on the analysis of data, it was found that the mean score of pre-test was 43.06, while the mean score of post-test was 91.45. The gain score was 48.39. It indicated that there was an improvement of students’ speaking ability. Moreover, the analysis of t-test showed that tscore>ttable or 5.37 > 1.69 at the level of significance 0.05 with the degree of freedom (df) 30. It is clear that the alternative hypothesis (Ha) is accepted. According to the findings, it can be concluded that Guessing Games is an effective strategy in teaching speaking to students, especially students at junior high school level.