本研究旨在探討後設認知教學策略對高中生英文作文的學習成效。研究者以桃園縣立永豐高中五年某班中的四十二位學生為對象，進行為時一學期共十五週，每週兩節課的實驗。教學實驗進行之前，全體學生接受研究者改編自Schraw and Dennison (1993)，O’ Neil and Abedi (1996)，Wey(1998) 所編製的後設認知量表，實施後設認知量表前測，並接受作文的前測。研究者根據作文前測的成績區分出能力高、中、低三組於教學實驗結束之後施以訪談。全體學生並於教學實驗結束之後，再度接受後設認知量表與作文的後測。以觀察其在策略教學後英文寫作表現與後設認知行為的差異情形。 本研究主要的發現下： 1.後設認知策略教學的確能夠有效提升高中生的英文寫作能力。 2.後設認知策略教學的確能夠有效增加高中生在英文寫作中的後設認知 程度。 3.高中生英文寫作表現的確與後設認知的成長有正相關。 4.學生對於後設認知策略教學均抱持正面的態度。 有鑑於此，本研究建議高中英文教師應用後設認知教學策略於高中英文作文教學中。 / This researcher explored the effectiveness of the metacognitive strategy instruction in senior high school writers’ performance, based on the theories of metacognitive strategies. Forty-two high school students in Yung-feng were selected to be subjects. Adapted from Schraw and Dennison’s Metacognitive Awareness Inventory (1993), O’ Neil and Abedi’s State Metacognitive Inventory (1996) and Wey’s Writing Self-Assessment Questionnaire (1998), Mtacognitive Awareness Questionnaires before and after Instruction, were used to measure students’ metacognitive awareness. To assess the effects of metacognitive strategy instruction on writing performance, forty-two pieces of writing were assigned in class and then scored based on criteria by the CRESST writing score guide: overall impression, quality and scope of content, organization and presentation of content, and mechanics. The Pair-Sample T test was performed to test the hypotheses in this study. The findings can be summarized as follows: (1) Metacognitive strategy instruction has positive effects on the students’ writing performance. (2) Metacognitive strategy instruction has positive effects on students’ metacognitive awareness. (3) Students’ writing performance proved correlated to their metacognitive awareness. (4) Students’ attitudes towards the metacognitive strategy instructions were generally positive. Thus, we recommend that metacognitive strategy instruction be used in English writing in senior high school.