The present research reveals that academic papers published at year-end on average receive systematically fewer citations than papers published at other times in the year. Using more than 200,000 papers  in econmics published between 1956 and 2010, the results of our analysis show that papers published between October and December on average get as much as 18.5% fewer citations than those published in the other months in the year. We refer to this phenomenon as the citation trap as there is no evidence that papers published at different times in the year differ in their acadmic quality. We propose that the current effect could arise because of the time window options in most online academic search engines: the specific setting of those options leads papers published at year-end to appear in the engines' search results for a systematically shorter period of time as compared to papers published at other months in the year. Our analysis reveals evidence that is consistent with the proposed mechanism and that rules out several alternative explanations. Implications of the current research for academia and possible solutions to mitigate the citation trap are discussed.