Social media platforms have been adapted into society in various ways during last two decades. Few studies have examined social media content from the perspective of the individual library professional, and in particular, from librarians’ social media posts about their work. This research explores social media complaints from library professionals to reveal insights into the areas of concern related to libraries as expressed in an informal, discursive style. Reddit data from three library subReddits was collected through a Python script. A total of 272 complaint posts with enough information were coded manually. A computational tool, Linguistic Inquiry and Word Count (LIWC), was also used to extract linguistic characteristics of each post. The majority of the sources of the complaint posts came from librarians (86.76%). The top five categories of the target of the complaints were patrons (27.94%), the poster’s organization (20.22%), the poster’s supervisor (11.03%), the library field (11.03%), and the poster’s coworkers (10.29%). The top four topics of the complaint posts were patron behavior (21.69%), negative work environment (16.18%), job expectations (11.76%), and service expectations (10.66%). Organizations should put into place mechanisms and processes through which employees may share their concerns and exercise their voice, with no retribution, to solve workplace problems.