Background: It was reported by clinicians working in the Ngorongoro Conservation Area that about 40% of Maasai pregnant women reporting at the Antenatal Clinic were diagnosed with oral thrush. However, it was not immediately determined what factors predispose these women to oral thrush. This study aimed at finding out the prevalence of oral thrush in the Maasai women community and the identification of predisposing factors. Methods: This was a cross sectional study done in the Ngorongoro Conservation Area among Maasai women of reproductive age (15–49 years). Convenience sampling technique was used to select participants from all participating villages. Participants were clinically examined for oral thrush lesions and a structured interview guide was used to collect information on age, parity, pregnancy status and history of breastfeeding. To explore the possible predisposing factors for oral thrush, anthropometric measurements including weight and height were taken and also blood samples were collected from participants and tested for HIV, syphilis and blood sugar. Multivariate logistic regression was used to obtain independent predictors of oral thrush. Results: The prevalence of oral thrush among study participants was 32%. Oral thrush prevalence was significantly higher in non-pregnant than pregnant women (p=0.000). Amongst the non-pregnant women, oral thrush was significantly higher in breastfeeding than the non-breast feeding participants. Univariate logistic regression showed that non-pregnant women had higher odds of getting oral thrush compared to pregnant women [OR 21.8; (95% CI 9.6, 49.6)]. Amongst the non-pregnant women, breastfeeding women had increased odds or higher chances of getting oral thrush compared to the non-breastfeeding women [OR 15.8; (95% CI: 7.2, 34.8)]. In the multivariate analysis, breastfeeding women adjusted odds ratio (AOR) 2.88; (95% CI: 0.99, 8.3) and non-pregnant women AOR 0.09; (95% CI: 0.03, 0.27). Two factors that predicted oral thrush are breastfeeding and not being pregnant. Conclusions: From the results, breastfeeding non pregnant women were at a higher risk of developing oral thrush. Possible predisposing factors are discussed.