Chronic obstructive pulmonary disease (COPD), the most common chronic respiratory disease, is expected to become the third leading cause of death worldwide in 2020. A prospective cohort study conducted in 2017 and 2018 aimed to identify factors associated with inhaler treatment adherence in patients with COPD in Cairo (Egypt). Physicians collected data regarding patient deaths, treatment-related adverse events, and patients' social support (no support, patient, support by spouse, children, and siblings) from their patients with COPD. The reason for treatment discontinuation was categorized as per patient decision or per physician decision. Adherence was categorized as treatment continued or treatment stopped. Patients who decided to stop treatment were considered non-adherent to COPD therapy. A total of 1311 patients as well as 98 physicians and 205 pharmacists were included. Pharmacists and social support (spouse, children/siblings) were identified as key positive factors in patients' decisions to adhere to their prescribed COPD treatment regimens. A total of 631 patients (48.1%) stopped the treatment, including 170 (27.0%) due to patient decision and 55 (8.7%) deceased. After Cox model analysis, a low number of patients (6-19) attended by the pharmacist was a significant predictive factor (hazard ratio [HR] = 1.40, 95% confidence interval [CI] = 1.03-1.91, p = 0.03) for deciding to stop treatment. A wife or husband (HR = 0.85, 95% CI = 0.72-1.02, p = 0.07) as well as children or brother/sister (HR = 0.77, 95% CI = 0.57-1.04, p = 0.08) provided a positive effect for continued treatment. Pharmacists are well positioned to play a role as an essential public health resource that can help improve adherence as well as social support that should be considered as an important component to improve adherence to long-term therapy in COPD as well as other chronic non-communicable diseases in low- and middle-income countries.