Background: Neonatal jaundice occurs worldwide and contributes significantly to neonatal morbidity and mortality. Recently, newborns are being discharged early from hospitals, so parents have the primary responsibility for early recognition, appropriate response and seeking proper treatment. Objectives: To assess parents' knowledge, attitude and practice towards NNJ in different regions in Saudi Arabia. Methods: This is a cross-sectional study involving 4413 expectant parents during July- September 2017 had been performed. A self-administered questionnaire was created to obtain respondents information. Descriptive statistics were used to describe the answers of participants in the study. Comparing the answers to different questions within different groups was done using Pearson chi-square test. Statistical significance was set at p =< 0.01 and analysis was performed using IBM SPSS statistics, version 23 (IBM, Armonk, NY, USA).  Results: Out of 4413 participants, females were (79.4%) while (20.6%) were males. Participants were from all regions of Saudi Arabia, with the highest percentage from central region (29.5%), most of them lived in cities (89.6%). Age group 20-30 years constituted (46.6%), and age above 50 years was 4.5% (p= <0.01). Most of the participants had a university level of education (76.6%). Relatives and friends were the main sources of knowledge for (52.6%) of the participants, followed by treating doctor in (29.8%). In (34%) of the participants' knowledge was gained after their child had NNJ, while in (42.1%) while their child was free of NNJ. Warning signs knowledge depended on the level of education and occupation where university graduates and health care workers were most knowledgeable and the difference was significant (p=<0.01).  Awareness about necessity and effectiveness of treatment were dependent on older age, occupation, and place of residence (p=<0.01). Hospital treatment was done only by (23.4%), believing that it wasn't a serious disease in (18.1%) of participants, while (5%) believed that it needed no treatment at all. Conclusion: Knowledge, attitude, and practice of parents in our study, depended on age, level of education, occupation, and place of residence might have contributed to the delayed appropriate management of severe hyperbilirubinemia. We recommend the engagement of health professionals in educational settings like seminars, workshops and periodical counseling sessions to provide appropriate knowledge to parents.