Infectious diseases are the leading cause of child mortality in Indonesia, yet many deaths can be prevented through immunization. The 2023 Indonesian Health Survey reported a national full basic immunization coverage of only 35.8%, a decrease from 57.9% in 2018 and far from the 100% target. Surakarta City achieved a coverage of 98.34% in 2023, showing strong regional commitment, although it still does not fully meet national goals. This study analyzes the influence of the Theory of Planned Behavior (TPB) on the use of immunization services for infants in Surakarta. Using a cross-sectional design, 200 mothers with infants aged 12–24 months were selected through multistage random sampling. Independent variables include intention, attitude, subjective norm, and perceived behavioral control; the dependent variable is the use of infant immunization services. Data were collected via structured questionnaires and analyzed using linear regression and path analysis. The study found that intention directly affects the use of immunization services (b=0.20; 95% CI=0.07 to 0.33; p<0.00). Attitude, subjective norm, and outcome evaluation indirectly influence immunization service use through intention. The path model demonstrated good fit (CFI = 0.979; TLI = 0.964; RMSEA = 0.079; SRMR = 0.037). Intention plays a crucial role in the use of immunization services, with attitude, subjective norm, and outcome evaluation affecting use through intention. The study model shows good fit. Increasing immunization uptake should focus on strengthening intention through positive attitudes, social norms, and education.