Background: Urinary tract infections (UTIs) are common bacterial infections, and rising antimicrobial resistance threatens effective treatment in resource-limited settings. Objective: This study determined the prevalence, antimicrobial resistance profiles, and risk factors associated with uropathogenic bacteria among residents of Kibra informal settlement, Nairobi. Methods: A cross-sectional mixed-methods study was conducted in Kibra informal settlement and the microbiology laboratory of a tertiary county hospital between November 2025 and February 2026. A total of 607 urine specimens were collected from symptomatic residents and processed using standard microbiological techniques. Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) 2023 guidelines. Additionally, 100 household respondents completed structured questionnaires on antibiotic-use practices, while 50 participants took part in focus group discussions exploring health-seeking behaviour, antibiotic acquisition and use, disposal practices, and barriers to appropriate antibiotic use. Quantitative data were analysed descriptively and inferentially, while qualitative data underwent thematic analysis. Results: Of 607 specimens, 150 (24.7%; 95% confidence interval 21.4–28.3) grew a bacterial uropathogen. Escherichia coli predominated (57.3%). Resistance was highest to ampicillin (92.0%), ceftriaxone (81.8%) and trimethoprim-sulfamethoxazole (74.7%), and lowest to nitrofurantoin (8.4%), amikacin (1.5%) and meropenem (0.0%). Multidrug resistance was 84.7% (127/150); 83.3% (90/108) of isolates from species in which screening is interpretable showed a phenotype consistent with extended-spectrum β-lactamase production. Among 100 respondents, 84.0% took an antibiotic for their last episode, 49.0% bought it without prescription and 42.0% completed the course. No socio-demographic factor was significantly associated with inappropriate antibiotic use (88.0%). F