Antimicrobial resistance is a major threat to global health in the 21st century. In the age of the internet and social media, infographics may constitute an effective educational resource for transmitting complete messages about antibiotics and antimicrobial resistance and driving behavioural change. We aimed to evaluate the infographics on antibiotics available on the internet in terms of their documentary quality, purpose, and appropriateness as educational tools for explaining the strategic lines defined in the World Health Organization Global Action Plan on Antimicrobial Resistance (GAP-AMR) and for conveying the One Health concept. We obtained the infographics for this cross-sectional study on 4 March 2021 by searching the terms “infographic” and “antibiotic” in Google Images. We verified infographic documentary quality by analysing the image, authorship, title, structure, date, and licence. To evaluate the purpose, we determined whether it coincided with one of the strategic objectives set out in the GAP-AMR. The degree of appropriateness depended on the type of key awareness message on antibiotic use. After obtaining these results, we performed a cross-sectional evaluation to determine how successfully these infographics conveyed the One Heath concept. We selected 247 infographics from 518 references. Of the included infographics, 97 (39%) were produced by public institutions; 58 (23%) read from left to right; 142 (57%) had an educational purpose; 156 (63%) focused on humans; 140 (57%) were subject to copyright; and 97 (39%) had no licence of any type. Almost one quarter (n = 57; 23%) included no key message on proper use of antibiotics. Infographics that included an author/promoter had a significantly higher mean number of messages that those without disclosure of authorship (1.67 vs. 0.50; p < 0.001). The infographics on antibiotics available on the internet are of moderate general quality. Most are produced by public institutions and have a clear and readable layout, but very few have a Creative Commons license to enable their reuse as informative material. The most common purpose is to improve awareness and understanding of antimicrobial resistance; few infographics focus on the remaining four strategic objectives of the GAP-AMR. It would be useful for authors of educational infographics on antibiotics to promote key messages related to antimicrobial resistance and the One Health concept, in accordance with the first objective of the WHO GAP-AMR.