Prompt treatment of pediatric pneumonia symptoms is a cornerstone of child survival programs but remains a challenge in Nigeria. Psychosocial influences, or ideations, directly influence pathways to care but have not been previously measured or examined for pediatric pneumonia. A two-stage cluster-sample cross-sectional population-based survey was conducted in Kebbi, Sokoto, and Zamfara States in September 2019. Across 108 enumeration areas, all households were enumerated to census pregnant women and randomly sample women with children under 2 years ("under-twos") for inclusion. Respondents were asked about pediatric pneumonia and other health-related behaviors and ideations developed using the Ideation Model of Strategic Communication and Behavior Change. Prevalence ratios for predictors of care-seeking from formal medical sources and antibiotic treatment for pneumonia symptoms among under-twos were calculated using mixed-effects Poisson regression models with robust error variance. Among 350 under-twos with pneumonia symptoms, 33.8% were taken to formal medical care and 38.0% used antibiotics. Women who positively viewed treatment efficacy and those who positively viewed health services quality had 1.35 (95% CI: 1.00-1.82; P = .050) and 2.13 (95% CI: 1.35-3.35; P = .001) times higher likelihood of attending formal medical sources, while women viewing peers as mostly attending drug shops had 29% lower likelihood. Perceived treatment efficacy and illness susceptibility were also significant predictors for antibiotic use. Program interventions focusing on increasing pneumonia knowledge alone may not be sufficient to improve care-seeking and treatment rates and should expand to address perceived and actual poor-quality health services and maternal beliefs about treatment efficacy, social norms, illness severity, and susceptibility.