葛梯爾問題（英語： ，又譯為蓋提爾問題），係現代知識論入面提到嘅一個關於知識定義嘅問題。1963年，美國哲學家愛德蒙德·葛梯爾喺一篇只有三頁紙嘅論文中質疑當時哲學界公認知識嘅定義：知識係得到證成嘅真信念（亦即係知識三要素，又叫做“JTB理論”）。佢嘅論文標題係：“得到證成嘅真信念就係知識嗎？”  。喺呢篇論文入面，葛梯爾提出咗兩個反例，去解釋就算得到證成嘅真信念，都未必係知識。呢篇論文引發咗哲學界一連串對知識定義嘅爭論，由此出現咗葛梯爾問題：“應該點樣去補充或者修改知識三要素，先可以完整噉定義知識概念？”
The Gettier problem is a question of the definition of knowledge mentioned in modern epistemology. In 1963, the United States philosopher Edmund · Gettier questioned the accepted definition of knowledge in philosophy at the time in a three-page paper: knowledge is a true belief that has been proven (that is, the three elements of knowledge, also known as uranium JTB theory). The title of his dissertation is: Is True Belief Proven by Anger Knowledge? Shhhhhh In this paper, Gettier presents two counter-examples to illustrate that even if true beliefs are proven, they are not necessarily knowledge. This paper sparked a series of debates in the philosophical community about the definition of knowledge, which led to the emergence of Gettier's question: how should uranium supplement or modify the three elements of knowledge in order to fully define the concept of knowledge?