Rabies remains a fatal yet preventable zoonotic disease, and understanding population-level knowledge, attitudes, and practices (KAP) is essential to guide national elimination strategies. This nationwide cross-sectional study assessed rabies-related KAP among 2116 residents across all major regions of Saudi Arabia. An online validated questionnaire measured sociodemographic characteristics and KAP indicators. Descriptive and inferential statistics, including logistic regression, were used to identify predictors of good KAP outcomes. Overall, more than half of participants demonstrated poor knowledge (54.9%), particularly regarding rabies etiology, transmission, and essential post-exposure wound care, while attitudes toward prevention were overwhelmingly positive (92%). Despite this, several unsafe practices persisted, including interaction with stray animals and use of traditional remedies. Good knowledge was significantly associated with higher income, pet ownership, and residency in the Central region, whereas younger age and Northern residency predicted poorer practices. Mediation analysis suggested that knowledge may partly explain (mediate) the association between sociodemographic characteristics and reported preventive practices; however, causal inference is limited by the cross-sectional design. These findings demonstrate substantial knowledge and behavioral gaps despite favorable attitudes and highlight the need for culturally tailored educational interventions, improved access to post-exposure prophylaxis, and strengthened One Health strategies to support rabies elimination in Saudi Arabia.