Background: The rapid global rise in electronic cigarette (e-cigarette) use has generated ongoing debate regarding its respiratory health effects. Although often marketed as a safer alternative to combustible cigarettes, emerging evidence suggests potential pulmonary consequences. Objective: This meta-analysis aimed to evaluate the association between e-cigarette use and respiratory symptoms or impaired pulmonary outcomes across observational studies. Methods: A systematic search of major electronic databases was conducted to identify studies examining respiratory outcomes among e-cigarette users compared with non-users. Eligible studies were screened according to predefined inclusion criteria. Pooled effect estimates were calculated using a random-effects model to account for between-study variability. Heterogeneity was assessed using standard statistical measures, and subgroup analyses were performed by age group. Publication bias was evaluated through funnel plot inspection. Results: The pooled analysis demonstrated a significant association between e-cigarette use and increased odds of respiratory symptoms and reduced pulmonary function. Although heterogeneity was observed across studies, the direction of effect remained consistent. Subgroup analysis indicated a comparatively stronger association among adolescents than adults, suggesting potential age-related vulnerability. Mechanistic evidence from experimental and clinical research supports biological plausibility, including oxidative stress, airway inflammation, epithelial dysfunction, and impaired innate immune responses. Conclusions: E-cigarette use is associated with measurable respiratory risk and cannot be considered physiologically neutral. While harm reduction potential may exist for established smokers, widespread use—particularly among adolescents—raises important public health concerns. Longitudinal research with standardized exposure assessment is needed to further clarify long-term respiratory outcomes.