The emergence of a monkeypox (MPOX) outbreak in 2022 represented the most recent recognizable public health emergency at a global level. Improving knowledge and attitude towards MPOX, particularly among healthcare workers (HCWs), can be a valuable approach in public health preventive efforts aiming to halt MPOX virus spread. The aim of the current study was to evaluate the knowledge and attitude of HCWs in Lebanon towards MPOX and to assess their conspiratorial attitude towards emerging virus infections (EVIs). The current study was based on a cross-sectional online survey distributed via Google Forms during September–December 2022 implementing a convenience sampling approach. The final study sample comprised a total of 646 HCWs: physicians (n = 171, 26.5%), pharmacists (n = 283, 43.8%), and nurses (n = 168, 26.0%), among others (n = 24, 3.7%). Variable defects in MPOX knowledge were detected, with a third of the participants having MPOX knowledge above the 75th percentile (n = 218, 33.7%). Satisfactory attitude towards MPOX (>75th percentile) was observed in less than a third of the participants (n = 198, 30.7%), while a quarter of the study sample endorsed conspiracy beliefs towards EVIs at a high level (>75th percentile, n = 164, 25.4%). Slightly more than two thirds of the participants agreed that MPOX vaccination should be used in disease prevention (n = 440, 68.1%). Better levels of MPOX knowledge and attitude were significantly associated with postgraduate education and older age. Physicians had significantly higher MPOX knowledge compared to other occupational categories. Less endorsement of conspiracies towards EVIs was significantly associated with male sex, occupation as a physician, and postgraduate education. Higher MPOX knowledge was associated with better attitude towards the disease. The current study showed unsatisfactory MPOX knowledge among Lebanese HCWs. Educational efforts can be valuable to improve the attitude towards the disease. Despite the relatively low level of embracing conspiracy beliefs regarding EVIs among HCWs in this study compared to previous studies, this area should be considered based on its potential impact on health-seeking behavior.