Background Self-medication with non-steroidal anti-inflammatory drugs (NSAIDs), proton pump inhibitors (PPIs), and antibiotics represents a growing public health challenge in India, where over-the-counter access is widespread and pharmacological literacy remains limited. Understanding self-medication behaviour across different population groups—including trained pharmacy students, the general public, and community pharmacists—is essential for designing targeted interventions. Objectives This study assessed the prevalence and patterns of self-medication, pharmacological awareness regarding NSAIDs, PPIs, and antibiotics, and community pharmacy dispensing practices, with the aim of identifying knowledge-practice gaps and evaluating intergroup associations through inferential statistical analysis. Methods A cross-sectional survey was conducted using a structured, validated Google Form questionnaire administered to 200 respondents across three groups: pharmacy students (n=122), pharmacists/medical chemists (n=5), and the general public (n=73). Data were analysed using descriptive statistics and inferential tests including Chi-Square test, Fisher’s Exact test, Mann-Whitney U test, Kruskal-Wallis test, and Spearman’s rank correlation at α = 0.05. Results Self-medication prevalence was 64.4% among the general public and 77.9% among pharmacy students for NSAIDs. Despite formal pharmacy enrolment, 52.5% of students had received no training in rational drug use, yet formal training showed no statistical association with NSAID self-medication behaviour (χ²=0.000, p=1.000). Only 37.0% of the general public correctly identified antibiotics as effective against bacterial infections, while 23.3% were aware of long-term PPI-associated risks. Significant findings included a positive correlation between counselling intent and medication safety attitude (ρ=0.193, p=0.033), and significant variation in regulatory support across antibiotic misuse groups (H=7.020, p=0.030). Conclusion A substantial knowledge-practice gap exists across all respondent groups. Pharmacological knowledge alone does not deter irrational self-medication behaviour. Structural interventions including stricter prescription enforcement, curriculum reform, and public medicine-literacy programmes are urgently required.