It was a cross-sectional survey conducted among 385 participants visiting tertiary care center from all over Nepal from February 2022 to May 2022. Modified Bloom's cut-off point was utilized to categorize the participants' overall knowledge, behavior, and practice. The chi-square (χ 2) test and odds ratio (OR) using binary logistic regression at 95% CI and Spearman's rank correlation coefficient test (r) were calculated wherever appropriate. More than three-fifths of the participants (248, 64.42%) demonstrated good behavior, whereas less than half of the participants showed good knowledge (137, 35.58%) and practice (161, 41.82%) about rational use of antimicrobials. Health professionals had higher knowledge (OR: 1.07, 95% CI: 0.70-1.62) and good behavior (OR: 0.42, 95% CI: 0.27-0.64) than other professionals (P<0.05). Those with higher income [≥50000 NRS (Nepalese rupees)] had good behavior (OR: 3.37, 95% CI: 1.65-6.87) and good practice (OR: 2.58, 95% CI: 1.47-4.50) scores than those with less monthly income (P<0.05). Similarly, higher educational degrees, viz. master's and/or above, had good behavior (OR: 4.13, 95% CI: 2.62-6.49) and good practice scores (OR: 2.55, 95% CI: 1.68-3.87). Additionally, there were significant positive correlations between knowledge (K), behavior (B), and practice (P) scores (r=0.331 for K and B, r=0.259 for K and P, and r=0.618 for B and P, respectively; P<0.05). The findings imply the demand for effective legislature, strict enforcement of the drug act, and proper implementation of plans and policies to curb antimicrobials misuse. Lack of execution of existing laws and the unawareness of the public led to the extravagant use of antimicrobials.