Background Mother-to-child transmission (MTCT) of the hepatitis B virus (HBV) is significant, as most infants infected at birth go on to develop chronic hepatitis B. Vaccination and antiviral treatment during pregnancy could primarily prevent vertical transmission. Therefore, the purpose of this study is to assess pregnant Jordanian females' knowledge, attitude, and practices (KAP) toward HBV. In addition, to explore the relationship between the level of KAP toward HBV infection and its predictors. Methods Our cross-sectional study was conducted among pregnant women in Jordan. We enrolled 621 participants between January and April 2023. Our survey was derived from a previously validated tool that was used to investigate a similar aim as our study. The survey was done via Google Forms (Google LLC, Mountain View, California, United States) and it contained questions divided into four main sections: participants' demographics, knowledge section, attitudes section, and practices section. Results The majority of participants have neither a personal nor family history of HBV, and only 91 (14.7%) of the participants had a medical degree. The overall knowledge, attitude, and practice (KAP) scores were low, as only 176 (28.3%), 315 (50.7%), and 244 (39.3%) of participants achieved high levels of knowledge, attitude, and practice scores, respectively. A significant association was found between knowledge level, practice assessment, and the following variables: age, educational level, job, study field, history of HBV in the family, and source of knowledge. Regarding attitude, a significant association was found with the job, study field, and source of knowledge. Conclusion This study found that pregnant women in Jordan had a low level of awareness of HBV infection. Thus, more efforts should be made to raise awareness about HBV among high-risk groups, especially pregnant women.