Background: “Chronic obstructive pulmonary disease (COPD)” is a well-known health problem for which cigarette smoking is a major risk factor. “Pulmonary function tests (PFTs)” are essential in assessing lung function and identifying respiratory diseases. This study aims to compare the results of PFTs between smokers and non-smokers. Methods: A total of 100 participants were recruited for this study, including 50 current smokers and 50 non-smokers. PFTs such as spirometry, lung volumes, and “diffusion capacity of carbon monoxide (DLCO)” were conducted. T-tests were used to compare the PFT results between smokers and non-smokers. Results: The study found that smokers had significantly lower values for “forced expiratory volume in one second (FEV1)” and “forced vital capacity (FVC)”, “total lung capacity (TLC)”, and DLCO when compared to non-smokers. In addition, smokers' FEV1/FVC ratios were considerably lower than those of non-smokers. Conclusion: The current findings demonstrate that smoking has a substantial negative impact on pulmonary function, as evidenced by the lower PFT readings in smokers. The results of this study underscore the importance of smoking cessation programs in enhancing lung health and preventing respiratory illnesses. In summary, smokers had considerably lower PFT values than non-smokers, indicating that smoking has an adverse effect on lung function.