Introduction. Hepatitis B virus disease is a viral infection caused by the hepatitis B virus (HBV), which is a major public health problem worldwide. According to the World Health Organization (WHO) estimate, two billion people worldwide have serologic evidence of past or present HBV infection. The risk of infection is high among health professionals due to the risk of occupational contact with fluids of infected patients and the risk of needle stick injury. This study is aimed at assessing HBV vaccination coverage and reasons for possible defiance of the vaccine among healthcare workers in Bosaso, Somalia. Methodology. An institution-based cross-sectional study was conducted by using a quantitative approach to identify hepatitis B virus vaccination coverage and reasons for vaccine defiance in Bosaso from September 2020 to November 2020. Healthcare workers (HCWs) in Bosaso city both in public and private health facilities who accepted to participate in this study were interviewed by using a structured questionnaire, and SPSS was used to analyze the collected data. Results. We found that only (16.4%) of HCWs were fully vaccinated. The main reasons for not taking the vaccine by the participants were the unavailability of the vaccine (42%), high vaccine cost (28.7%), lack of time (20.7%), and fear of vaccine side effects (7.5%). The majority (69.7%) of HCWs demonstrated good knowledge about HBV infection. The vaccination uptake was significantly higher among midwives (
p
=
0.02
;
OR
=
1.21
;
95
%
CI
=
1.39
−
67.41
) and individuals aged under 30 years (
p
=
0.03
;
OR
=
8.6
;
95
%
CI
=
1.17
–
63.26
). Conclusion. Our study revealed that vaccination coverage of HCWs in Bosaso was very low because of the unavailability of vaccines, high cost of the vaccine, lack of time, and fear of vaccine side effects. Therefore, the development and implementation of policies related to HBV vaccination are recommended.