Introduction Globally, Sierra Leone has some of the worst maternal and child health indicators. The situation is worsened by a dearth of evidence about the level of continuum of care, an evidence-based intervention aimed at reducing maternal and perinatal morbidity and mortality. Hence this study aimed to assess the level of and factors associated with continuum of maternal and newborn care in Sierra Leone. Method This study analyzed secondary data from the 2019 Sierra Leone Demographic Health Survey. Analysis was restricted to women who had a live birth in the 5 years preceding the survey (n = 7326). Complete continuum of care was considered when a woman reported having had at least eight antenatal care contacts, skilled birth attendance and mother and baby had at least one postnatal check-up. Bi-variable and multivariable logistic regression were performed using the statistical package for the social sciences software version 25. Results Only 17.9% (95% CI: 17.4-19.1) of the women utilized complete continuum of care for maternal and newborn health services in Sierra Leone. About 22% (95% CI: 21.3-23.1) utilized 8 or more antenatal care contacts, 88% (95% CI: 87.9-89.4) had skilled birth attendance while 90.7% (95% CI: 90.2-91.5) and 90.4% (95% CI: 89.9-91.2) of mothers and neonates utilized postnatal care respectively. Having started antenatal care within the first trimester (aOR 1.71, 95% CI: 1.46-2.00), being resident in the Southern region (aOR 1.85, 95% CI: 1.23-2.80), belonging to richer wealth quintile (aOR 1.76, 95% CI: 1.27-2.44), using internet (aOR 1.49, 95% CI: 1.12-1.98) and having no big problems seeking permission to access healthcare (aOR 1.34, 95% CI: 1.06-1.69) were significantly associated with utilization of continuum of care. Conclusion The overall completion of continuum of maternal care is low, with ANC being the lowest utilized component of continuum of care. These findings call for urgent attention for maternal health stakeholders to develop and implement tailored interventions prioritizing women empowerment, access to affordable internet services, timely initiation of ANC contacts, women in developed regions such as the Western and those from poor households.