PurposeGoogle Maps is a web platform that allows users to review businesses and services, including libraries. Given the impact of online reviews on the corporate reputation of companies and institutions, it is important to understand how library users disseminate and process reviews on online sites. This study explores whether Google Maps is being used by users of public libraries in the city of Barcelona (Spain) to share their views on libraries' facilities and services and what perception of the library they transmit.Design/methodology/approachRecords corresponding to the 40 public municipal libraries in Barcelona were retrieved from Google Maps. For each library, the average “rating” (a quantitative assessment of the library) and a sample of the ten most recent “reviews” (a text and/or photograph(s) that accompanies the rating) were analysed. Reviews were categorised into eight categories: “children's areas”, “collections”, “location”, “facilities”, “general reviews”, “opening hours”, “staff” and “technology”.FindingsAll of the city's 40 public libraries are present in Google Maps and have been reviewed by users, usually with high ratings. The number of replies to users' reviews by library managers is negligible. Reviews with low ratings tend to be longer than those with high ratings. In the reviews, children's areas, collections and library location are given positive ratings. Facilities also receive positive reviews, although to a lesser extent, and two issues receive criticism: noise and lack of seating space for studying. Three aspects of the libraries attract similar numbers of positive and negative reviews: staff, opening hours and technology. The study concludes that Barcelona's public libraries should devote more resources for keeping the information in their profiles updated. They should also monitor users' opinions and create guidelines to offer feedback, especially to negative reviews.Research limitations/implicationsThe research is limited by being restricted to a single platform (Google Maps) and a single city (Barcelona). Those writing reviews in Google Maps may not constitute a representative sample of library users. “Local guides”, who tend to award higher ratings than other users, participate in a programme that allows them to earn points that may be exchanged for benefits. Therefore, it is possible that at least some “local guides” publish reviews on public libraries they hardly know (if at all) just to obtain benefits. Similarly, the large number of users commenting on study spaces suggests that young people may be over-represented.Originality/valueMany studies have analysed transaction data in online library settings, including visits, searches, downloads, etc. but there are no examples of analyses of user-generated content such as texts or photos uploaded to review sites and social media. The results of this study will help to improve the understanding of how library patrons see public libraries and to design effective strategies to respond to and generally manage their suggestions and complaints.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/OIR-09-2019-0291