Background and Objectives: Inadequate treatment of asthma and chronic obstructive pulmonary disease (COPD) might have a negative impact on their progression. Inhalation therapy is the cornerstone of pharmacotherapy for these conditions. However, challenges such as low adherence, negative attitudes, and misconceptions about inhaled medications still persist, impeding effective disease management. This study aimed to evaluate adherence, ascertain the level of disease control in asthma and COPD, explore potential misconceptions surrounding inhalation therapy among patients with obstructive lung diseases and the general population in Vojvodina, and evaluate the reliability of newly developed questionnaires employed in the study. Materials and Methods: This cross-sectional study utilized a battery of questionnaires encompassing sociodemographic data, the Asthma Control Test (ACT), the COPD Assessment Test (CAT), along with two novel questionnaires-one for assessing adherence and another for analyzing attitudes toward inhalation therapy. Statistical analyses were conducted using SPSS software, version 25.0. Results: The average ACT score among patients with asthma was 17.31, while it was 19.09 for the CAT questionnaire among COPD patients. The composite score on the newly developed adherence assessment questionnaire was 2.27, exhibiting a reliability coefficient lower than recommended (α = 0.468). Significant statistical differences emerged among sample subgroups regarding attitudes and misconceptions toward inhalation therapy. The reliability coefficient for this questionnaire was deemed satisfactory (α = 0.767). Conclusions: Adherence rates were notably suboptimal in both subgroups of the studied population. The disease control levels were higher among asthma patients, while they exhibited less prevalent misconceptions regarding inhalation therapy compared to COPD patients and the healthy population.