Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases which are characterized by chronic inflammation and an increase in mucus production, and are highly prevalent conditions. Despite recent advances and multiple available therapies, there remains a significant unmet medical need. Over the past 40 years, the introduction of new classes of safe and effective therapy is insufficient. In spite of the high burden of asthma and COPD among patients, there are fewer new approved therapies in comparison to cardiovascular, metabolic and neurological diseases due to few drug candidates and a higher failure rate in the development of respiratory medicine. Lung diseases are amongst the leading causes of death globally with asthma being one of the most prevalent respiratory diseases, which affects people of all ages but, despite effective therapies available, many patients are poorly controlled and have a low quality of life. COPD is currently ranked as the fourth cause of death worldwide and predicted to become the third leading cause of death in 2030. The development of more effective treatments is urgently needed in order to reduce the high mortality rate and the enormous suffering from asthma and COPD. Various inhalation devices with different classes of medications are the foundation as therapies in both asthma and COPD. This article gives a comprehensive review of the promising inhaled therapies in the treatment of asthma and COPD. However, the lack of disease control in asthma and COPD patients may be due to numerous reasons. The association between non-adherence to guidelines on the part of the health care provider and poor inhalation technique and/or non-adherence to the prescribed treatment plan by the patients is common. It is therefore essential to discuss the different delivery systems and the methods used in asthma and COPD patients.