Although Jordan has applied lockdown in response to COVID-19 pandemic, many people were not adherent to the quarantine. We aimed to examine the attitudes of the Jordanians and how these attitudes can predict their adherence using the health belief model (HBM). A cross-sectional study of 5057 participants using an internet-based questionnaire was conducted during lockdown. Multivariable ordinal regression analyses were used to estimate predictors of adherence to home quarantine. Overall, 646 (12.8%), 2078 (41.2%), and 2317 (46%) of participants showed poor, intermediate, and strict adherence, respectively. Of the HBM constructs, seriousness (β= 0.116, 95% CI 0.027 to 0.205), benefits (β= 0.056, 95% CI 0.002 to 0.110) and barriers (β= -0.025, 95% CI -0.035 to -0.015) were significant predictors. We identified income insecurity (β= -0.096, 95% CI -0.144 to -0.046), social withdrawal (β= -0.062, 95% CI -0.121 to -0.004), religious concerns (β= -0.149, 95% CI -0.202 to -0.096) and health consequences (β= 0.065, 95% CI 0.011 to 0.11) as barriers. Governmental instructions were the only predictive external cue (β= 0.055, 95% CI 0.004 to 0.014). Our findings suggest that a high number of Jordanians are adherent with the quarantine, demonstrating the ability of governmental policies in tackling potential barriers.