Background <p>Lithium prescription rates have witnessed a significant downward trend over the years in different continents despite evidence of its clinical efficacy in the acute and long-term maintenance treatment of Bipolar Disorder (BD). Nigeria has a paucity of data on lithium use in BD management. Hence, we aim to investigate the lithium prescription rate and factors influencing its use among Nigerian psychiatrists and trainee psychiatrists.</p> Methods <p>A cross-sectional survey involving 203 respondents working in different accredited psychiatric training facilities in Nigeria was conducted between April and May 2024 using a predesigned online Google form. Information relating to lithium use in managing the different phases of BD and factors influencing its use were assessed.</p> Results <p>The mean age of the respondents was 37.98 (± 6.85) years. The lithium prescription rate is low (10.89%). There is a significant association between the respondents’ awareness of clinical practice guidelines (CPG) and good adherence to CPG (<i>p</i> = 0.003), but this did not significantly influence lithium prescription among them. Older years of practice influence prescribing lithium (<i>p</i> = &lt; 0.001). Monitoring and availability of lithium constituted significant concerns for lithium use, among other factors (<i>p</i> = 0.032).</p> Conclusion <p>The study revealed a low lithium prescription rate among Nigerian psychiatrists and trainee psychiatrists compared to international studies. There is a need for concerted efforts towards addressing the identified factors. A review of the existing local CPG in line with the best evidence is warranted for improved clinical outcomes.</p> Ethics registration <p>The study was approved by the Hospital Research and Ethical Committee (HREC) of the University of Port Harcourt Teaching Hospital (UPTH) with approval protocol number (UPTH/ADM/90/S.11/VOL.XI/1688).</p> Clinical trial number <p>Not applicable.</p>