本文旨在探討情境推論策略對台灣國中生字彙學習及閱讀理解兩方面的成效。本研究結果希望對英文老師在單字及閱讀教學上有很大的啟示作用及幫助。 本實驗的研究對象為台北縣某國中75位國三學生，所有受試者依據其原班級隨機分派為實驗組及控制組，實驗組接受情境推論策略訓練，而控制組則採用傳統教學法。在教學活動前後，實驗組及控制組的所有學生皆施予Paribakht和 Westche設計的字彙知識等級測驗，猜測字義測驗，閱讀理解測驗及英語學習背景問卷，實驗組則於後測時另外接受對此訓練活動的問卷調查。 本研究結果顯示：(一)實驗組在在接受「情境推論策略」訓練後於字彙學習上有顯著差異，亦即「情境推論策略」的教學有效增進學生字彙學習表現。(二)實驗組在接受「情境推論策略」訓練後，在猜測字義的表現上有顯著的進步。(三)在五種情境線索的題目表現，實驗組在「同義線索」和「定義線索」的題目表現上最好，而在「解釋線索」的題目表現上較不理想。至於五種情境線索的運用，實驗組較能正確使用「語調線索」，而較不會正確使用「解釋線索」。(四) 實驗組在接受「情境推論策略」訓練後，於閱讀理解表現上有顯著進步，，亦即「情境推論策略」的教學有效增進學生閱讀理解。(五)從反應問卷中顯示，接受此一策略訓練活動後，大部分的學生對於「情境推論策略」教學傾向於正面的肯定，並期望在未來英語課程中能繼續進行此教學活動。但部分學生對於在閱讀中碰到不認識單字仍有些許不安。 根據上述研究結果，本研究建議國中英語教師可以運用「情境推論策略」教學增進學生字彙學習和猜測字義能力，以及加強他們對於閱讀理解的表現和對英文學習的正面肯定。同時，為了能讓「情境推論策略」在學生字彙學習上發揮最大效益，教師應考慮字彙練習及字彙在文章中重複出現的重要。 / The present study aims to explore the effectiveness of contextual inference strategy (CIS) on vocabulary learning and reading comprehension of junior high school students in Taiwan. Two third- grade junior high school classes were selected as one experimental group and one control group. The research methods involved word-guessing pre- and post-test, vocabulary pre- and post-test, reading comprehension pre- and post-test, and questionnaires. The data analyses were descriptive statistics, Paired Sample T-test, and Independent Sample T-test. Based on the results of this study, major findings are summarized as follows. First, the CIS instruction led to greater gains in learners’ vocabulary knowledge than traditional instruction did. Second, CIS instruction had a significant effect on the experimental group’s word guessing abilities. Third, the participants performed better in the questions of synonym and definition clues while they were not good at questions of explanation clues. As for their use of contextual clues, the correctness rate of mood or tone clue ranks the highest while the explanation clue the lowest. Fourth, the two groups’ scores of the post-reading comprehension tests showed significant difference, indicating participants who were instructed with CIS performed better in the reading comprehension than those who didn’t. Fifth, according to the response questionnaire, most students considered CIS instruction helpful and gave positive responses to this training activity. The aforementioned findings in this study suggested that junior high school teachers could adopt CIS training to enhance students’ vocabulary learning and word-guessing abilities, and to reinforce their reading comprehension and positive attitudes toward English learning. Also, to help students perform better in vocabulary learning, teachers could implement focused instruction, such as redundant presentation and exercises.