The current monkeypox epidemic is most prevalent among men who have sex with men (MSM). PrEP users and MSM with HIV (MSMHIV) are considered at highest risk of monkeypox infection in the Netherlands, and are being targeted for monkeypox vaccination. Together with the epidemiological evidence, perceived concern and risk are also relevant for decision making about health behaviour, e.g., vaccination uptake. It is thus timely to examine which subpopulations among MSM consider themselves to be most at risk and are most concerned about monkeypox. This study aimed to help determine if the current measures to curb the epidemic are successfully targeted or not in the Netherlands. We conducted an online survey among 394 MSM living in the Netherlands. We first calculated the prevalence and standardised prevalence ratio (SPR) of high perceived monkeypox concern/risk by PrEP-use and HIV status. We then conducted two multivariable logistic regression analyses to investigate perceived monkeypox concern/risk and their potential socio-demographic/behavioural/health/psycho-social determinants. Among the included MSM, 52% showed high perceived concern about and 30% showed high perceived risk of monkeypox infection. PrEP users (SPR = 0.83) showed a significantly lower chance of perceived concern; in addition, MSMHIV (SPR = 2.09) were found to have a significantly higher chance of perceiving high risk of monkeypox infection. In the multivariable logistic analyses, non-PrEP users (aOR = 2.55) were more likely to perceive higher concern, while MSM who were retired (aOR = 0.23) and who had had chemsex recently (aOR = 0.63) were less likely to perceive higher concern. MSMHIV (aOR = 4.29) and MSM who had an unknown/undisclosed HIV status (aOR = 6.07), who had attended private sex parties (aOR = 2.10), and who knew people who have/had monkeypox (aOR = 2.10) were more likely to perceive a higher risk for monkeypox infection. We found that high perceived risk (aOR = 2.97) and high perceived concern (aOR = 3.13) were correlated with each other. In sum, only one-third of MSM living in the Netherlands considered themselves at high risk of monkeypox infection, and only half of them reported high concern. We identified a potential discrepancy between “actual risk” and perceived risk of and concern about monkeypox among MSM in this early stage of the monkeypox epidemic in the Netherlands, especially among PrEP users and MSMHIV. More refined public health communication strategies may be needed to improve the understanding and knowledge of the “actual risk” of monkeypox infections among MSM sub-populations, to facilitate health behaviour uptake.