The aim of this study is to reveal the perceptions of high school teachers about the concept of "hidden curriculum" through metaphors. The phenomenological research design was applied in this study. The study was carried out with the participation of 128 high school teachers. The study group was determined using a convenience sampling model. The study data were obtained by completing the blanks in the sentence 'hidden curriculum is like …because...'. The participants were asked to write a metaphor about the hidden curriculum in the first blank and explain why they wrote this metaphor in the second blank. Content analysis was used to analyze the obtained data. Categories were constituted by classifying the metaphors according to their common characteristics. Metaphors of the participants regarding the hidden curriculum were gathered in the categories of "invisible factor", "negative associations", "guiding for school", "school climate", "an object", "acting as a function", "powerful authority", "a part of daily life", "integral element of curriculum" and "building commitment". The participants mostly used metaphors of "invisible power", "atmosphere of school", "soul'', "virus", "rainbow", "guide", "secret message", "law" and "custom". When the sentences of metaphors made were examined, it was determined that the participants had both positive and negative perceptions regarding the hidden curriculum.