The aim of this study was to measure the uptake of influenza vaccine and to assess knowledge, attitudes, and practices towards influenza vaccine among adults attending primary healthcare centres in Dammam, Saudi Arabia. The study was conducted at two primary healthcare centres in 2017 and 2018. Participants completed a self–administered questionnaire about the influenza vaccine. Of the 279 participants, 50.4% had received an influenza vaccine at least once, and 57% have good knowledge about the vaccine. The combined attitudes and practice score were higher among those who were more knowledgeable about the influenza vaccine. The most common sources of information were an awareness campaign (59.0%) and media (22.6%). Barriers to vaccination included a perception of not being at risk of influenza (18.6%), a lack of awareness of the vaccine (11.1%), and a fear of side effects (8.2%).