BACKGROUND: HIV testing among women in sub-Saharan Africa varies widely, with Sierra Leone having lower rates than other countries. This study explores geographic variations and determinants of HIV testing among women aged 15-49 in Sierra Leone. METHOD: The study utilized data from the 2008, 2013, and 2019 Sierra Leone Demographic Health Surveys, comprising 39,606 women aged 15-49. Spatial autocorrelation and Moran's I were used to analyze the distribution of this outcome, while mixed-effect multi-level binary logistic regression assessed the factors associated with ever-tested for HIV. The findings were reported as adjusted odds ratios (aOR) with a 95% confidence interval (CI). RESULTS: This study found that 21.47% of the study population comprised young women aged 15-19, and 53.62% had no formal education. Ever tested for HIV drastically increased from 13% in 2008 to 56% in 2019. HIV testing hotspots expanded from the Western urban and rural areas in 2008 to include districts like Port Loko, Kambia, and Bo by 2019, with a national testing pooled prevalence of 45.5% [44.2, 46.8]. The pooled regression analysis shows that women aged 20-34 had higher odds of testing than those aged 15-19, while those aged 40-49 had lower odds. Higher education, marriage/cohabitation, media exposure, parity, sexual activity, recent healthcare visits, condom use, STI history, larger households, female-headed households, and higher wealth indices were associated with higher odds of testing. Testing odds were higher during the 2013 and 2019 survey years compared to 2008. Conversely, Muslims, women with challenges accessing healthcare, and those in rural areas had lower odds of being tested. CONCLUSION: From 2008 to 2019, the rate of women aged 15-49 years ever tested for HIV showed a significant increase. The expansion of HIV testing hotspots highlights progress in geographic coverage, but disparities remain, particularly in rural areas. Younger women (aged 20-34) and those with higher education, wealth, or access to healthcare services were more likely to be tested, underscoring the influence of socioeconomic and structural factors on testing uptake. The lower odds of testing among older women and Muslims point to the need for targeted interventions addressing cultural barriers. Media exposure, parity, and sexual activity emphasize the role of reproductive health and awareness in promoting testing. Efforts to improve access to healthcare in rural areas and address logistical challenges, such as distance to health facilities, are critical for equitable HIV testing coverage. Strengthening community-based outreach and culturally sensitive programs could further close the gaps in testing uptake. The sustained increase in testing prevalence from 2008 to 2019 reflects progress but also highlights the need for continuous investment in HIV testing programs.