Background: Monkeypox disease (MPD) recently re-emerged in May 2022 and caused international outbreaks in multiple non-endemic countries. This study aimed to assess the Saudi Arabian public and healthcare workers (HCWs) knowledge about MPD and their information-seeking attitudes before any cases were yet reported in Saudi Arabia. Methods: This online survey of HCWs and the public in the Kingdom of Saudi Arabia (KSA) was conducted from May 27 to June 5, 2022. The survey tool was adopted from our published research on COVID-19 with modifications related to the new MPD outbreak, which was validated for content, language, and consistency. Participants were invited by convenience sampling techniques through various social media platforms (i.e., Twitter and WhatsApp groups) and email lists. Variables surveyed included participants' sociodemographic and job-related characteristics, COVID-19 infection status, and advocacy for MPD vaccination. Multiple questions assessing the participants' knowledge related to MPD and (MPV) in terms of transmission, vaccination information by HCWs, and required isolation precautions. Finally, a Generalized Anxiety Disorder (GAD7) score was calculated. We then assessed the independent variables associated with participants' attitudes to seek more information about MPD, and those associated with knowledge scores. Results: A total of 1546 participants completed the public survey, and 61.3% showed interest in seeking more information about MPD. Of the participants, 48.7% knew that MPD could be transmitted before skin blisters appear, and 62.7% inferred that skin lesions are infectious. Only 38.1% inferred that touching contaminated surfaces, and 46.5% knew that sexual contact is a mode of transmission. 56.6% falsely believed the old smallpox vaccine is not effective against MPD. Public participants' overall mean knowledge score of MPD was 4.88 of 9 points. In contrast, the mean score of the knowledge of the 1130 HCWs was 14.4 of 28. Among HCWs, 28.3% correctly answered that the Jynneos vaccine has activity against MPD and 79.7% incorrectly answered that VARIVAX, a chickenpox vaccine, is effective against MPD. In addition, 74.2% of HCWs perceived the need to seek more information about MPD. Male HCWs had significantly lower mean knowledge scores compared to females. Physicians and HCWs' self-rated high awareness of MPD correlated positively and significantly with their knowledge score. Conclusion: In this study, the general public and HCWs had a moderate level of knowledge about MPD. The knowledge gaps among HCWs were evident in the clinical presentation of patients and vaccinations. Both groups reported a desire to seek more information about MPD, but this did not correlate with knowledge scores. It is important to have further education and intensification of campaigns to enhance awareness of MPD. It is also crucial to have further studies evaluate the knowledge of both groups over time.