Obstetric fistula is a devastating childbirth condition that results from prolonged obstructed labour without timely medical intervention, leading to a tear between the birth canal and the bladder or rectum. It is a public health issue, particularly in low-income countries with limited access to quality maternal healthcare. This study aims to assess knowledge of fistula symptoms among women who had a fistula and its associated factors in Sierra Leone. Cross-sectional data from the 2019 Sierra Leone Demographic and Health Survey was used for the study. Our study comprised 15,574 reproductive women aged 15 to 49. Using a four-modelled approach, a mixed-effect multilevel binary logistic regression analysis was performed to assess the factors associated with knowledge of fistula symptoms among women who had a fistula. The results were presented as adjusted odds ratios with a 95% confidence interval. The proportion of knowledge of fistula symptoms among women who had a fistula was 57.5% [55.3,59.7] in Sierra Leone. Women aged 20-49, particularly those between 40-44 [aOR = 2.82; 95% CI: 2.13, 3.73], were more likely to be aware of knowledge of fistula symptoms among women who had a fistula compared to teenagers (15-19). Women with higher levels of education [aOR = 2.07; 95% CI: 1.49, 2.88] were more likely to be aware of knowledge of fistula symptoms among women who had a fistula than those without education. Working women [aOR = 1.33; 95% CI: 1.14, 1.56], those who listened to the radio [aOR = 1.47; 95% CI: 1.30, 1.67] or used the internet [aOR = 1.64; 95% CI: 1.32, 2.05], and those with a high number of lifetime births [aOR = 2.00; 95% CI: 1.57, 2.54] were more likely to be aware of knowledge of fistula symptoms among women who had a fistula. Women who had ever had sex [aOR = 2.19; 95% CI: 1.73, 2.77], were pregnant [aOR = 1.37; 95% CI: 1.13, 1.66] or had terminated a pregnancy [aOR = 1.30; 95% CI: 1.07, 1.59] were more likely to be aware of knowledge of fistula symptoms among women who had a fistula. A female household head [aOR = 1.20; 95% CI: 1.05, 1.38] was associated with a higher likelihood of knowledge of fistula symptoms among women who had a fistula. On the other hand, larger household sizes [aOR = 0.86; 95% CI: 0.75, 0.97] and living in the Western region [aOR = 0.48; 95% CI: 0.31, 0.75] were associated with a lower likelihood of knowledge of fistula symptoms among women who had a fistula. Most reproductive-aged women in Sierra Leone have knowledge of fistula symptoms among women who had a fistula. Factors such as age, education, occupation, media exposure, parity, sexual activity, pregnancy status, abortion history, ethnicity, household structure, and geographic location influence the knowledge of fistula symptoms among women who had a fistula. Based on these findings, the government and partner organisations in Sierra Leone should implement comprehensive health education programs targeting reproductive-aged women, with a specific focus on obstetric fistula prevention, symptoms, and available treatment options.