The aim of this study was to evaluate Antibiotic Self-medication Practice (ASMP) and its associated factors among adult patients suspected of urinary tract infection (UTI) in Addis Ababa, Ethiopia. A multi-center cross-sectional study was conducted between November 2020 and August 2021. Data were analyzed using SPSS 25. Simple and multiple binary logistic regression analyses were performed. The magnitude of the associations was quantified using an adjusted odd ratio (AOR) with a 95% confidence interval (CI). Urine samples with significant growth (>105cfu/mL) were subjected to biochemical identification of Gram-negative and Gram-positive bacteria. Resistance data were interpreted according to the Clinical Laboratory Standards Institute. A total of 531 adult patients participated. The mean age (± SD) was 43.74 (± 16.16) years. The majority (368, 69.3%) of the patients were female. The prevalence of ASMP was 10.4%. Nearly 80% of the patients had poor knowledge of antibiotics. The most self-reported antibiotic was amoxicillin (28, 50.9%). The primary reason for ASMP was past experience with drugs (29, 52.7%). Among the self-medicating, forty-eight (87.3%) patients reported that ASMP was unacceptable. Statistically, patients whose age (50 years and older), income (4000 birrs and below), and no history of UTIs were associated with ASMP. In addition, 106/129 (82.2%) bacteria isolates were MDR. The two commonly isolated bacteria were Escherichia coli (88, 68.2%) and Klebsiella pneumoniae (10, 7.8%). E. coli (91%) was ampicillin-resistant and 100% resistant to amoxicillin and doxycycline. The K. pneumoniae isolates were 100% ampicillin-resistant, amoxicillin-resistant, and doxycycline-resistant. Nine (8.5%) patients with MDR bacteria had ASMP. Almost one-third of the bacteria resisted six antibiotics (33.3%). ASM for UTIs is a common practice in Addis Ababa. Some self-medicated patients developed MDR UTIs. Escherichia coli and Klebsiella pneumoniae were resistant to most of the antibiotics. Low-income and elderly patients, in particular, constitute the target population for risks of ASMP.