: Background: The goal of the present study was to estimate the prevalence of patient and physician related variables associated with antibiotic prescriptions in patients diagnosed with acute lower and upper respiratory tract infections (ALURTI), treated in general practices (GP) and pediatric practices, in Germany. Methods: The analysis included 1,140,095 adult individuals in 1237 general practices and 309,059 children and adolescents in 236 pediatric practices, from the Disease Analyzer database (IQVIA), who had received at least one diagnosis of an ALURTI between January 1, 2015 and March 31, 2019. We estimated the association between 35 predefined variables and antibiotic prescription using multivariate logistic regression models, separately for general and pediatric practices. The variables included the proportion (as a percentage) of antibiotics or phytopharmaceuticals on all prescriptions per practice, as an indicator of physician prescription preference. Results: The prevalence of antibiotic prescription was higher in patients treated in GP (31.2%) than in pediatric practices (9.1%). In GP, the strongest association with antibiotic prescription was seen in the practice preference for antibiotic use, followed by specific diagnoses (acute bronchitis, sinusitis, pharyngitis, laryngitis, and tracheitis), and higher patient age. In pediatric practices, acute sinusitis and bronchitis were the variables with the strongest association, followed by practice preference for antibiotic prescription. The strongest association with the non-prescription of antibiotics was practice preference for phytopharmaceuticals and the specific diagnosis of a viral infection. Conclusion: This study shows a high prevalence of antibiotic prescribing for patients with ALURTI in a primary care setting, especially in adult patients; physician related factors play an important role that should be addressed in interventions to reduce potentially inappropriate antibiotic prescribing.