This study was motivated by the low self-confidence and low fluency in speaking English shown by the eleventh-grade students of class XI F2 at SMA Negeri 3 Panyabungan. The study aimed, first, to describe the students’ confidence and fluency in speaking before the use of comic strips, and second, to examine how the use of comic strips could improve their confidence and fluency. The study employed classroom action research based on the model of Kemmis and McTaggart, carried out in two cycles, each consisting of planning, action, observation, and reflection. The subjects were the twenty-six students of class XI F2. The data were collected through a speaking test scored with Brown’s fivecomponent rubric, a self-confidence questionnaire based on Lauster’s five indicators, observation, and documentation, and were analysed both quantitatively and qualitatively. The findings showed that, before the intervention, the students’ speaking ability and self-confidence were low, with the class average below the Minimum Mastery Criterion and the confidence average in the low category. After the use of comic strips, both improved progressively: classical completeness in speaking rose from 0% in the preliminary study to 19.2% in Cycle I and 100% in Cycle II, while the class confidence average rose from the low category to the moderate and then to the high category, so that both criteria of success were achieved in Cycle II. The improvement is interpreted through the strengthening of the students’ self-efficacy for speaking. It is concluded that the use of comic strips effectively improves the students’ confidence and fluency in speaking English.