Spanish-speaking individuals may experience language-based disparities related to elective orthopaedic procedures. Because patients often seek online health information, we assessed the readability, credibility, and quality of Spanish-language educational websites for knee arthroplasty. We queried "Google," "Yahoo," and "Bing" using the term "reemplazo de rodilla" (knee replacement in Spanish) and extracted the top 50 websites per search engine. Websites were categorized by information source (physician/community hospital, university/academic, other) and presence of HONcode certification. Information was assessed for readability (Fernández-Huerta formula), credibility (Journal of the American Medical Association benchmark criteria), and quality (Brief DISCERN tool); scores were compared between the categories. A total of 77 unique websites were included (40.3% physician/community hospital, 35.1% university/academic). The median readability score was 59.4 (10th to 12th-grade reading level); no websites achieved the recommended level of ≤6th grade. The median Journal of the American Medical Association benchmark score was 2 (interquartile range 1 to 3), with only 7.8% of websites meeting all criteria. The median Brief DISCERN score was 16 (interquartile range 12 to 20), with 50.7% meeting the threshold for good quality. University/academic websites had better readability (P = 0.02) and credibility (P = 0.002) but similar quality (P > 0.05) compared with physician/community hospital websites. In addition, HONcode-certified websites had better quality scores (P = 0.045) but similar readability and credibility (P > 0.05) compared with noncertified websites. We identified limitations in readability, credibility, and quality of Spanish-language online educational resources for knee arthroplasty. Healthcare providers should be aware of these patient education barriers when counseling patients, and efforts should be made to support the online information needs of Spanish-speaking orthopaedic patients and mitigate language-based disparities.