The medicines employed for the therapy of asthma, COPD, and ACO are mainly bronchodilators such as beta2-agonists and muscarinic antagonists, or anti-inflammatory steroids utilizing an inhalation route. Unlike systemic treatments, inhaled medicines are rapidly directed to the airways, allowing for a quick onset and limited potential side effects. ICS are now the first-line of therapy for asthma, and inhaled LABA with a low dose of ICS are commonly prescribed to asthma patients. By contrast, the primary medical treatment for COPD are long acting bronchodilators. ACO is when two bronchial inflammatory disorders coexistence in the same patient. Although the precise definition of asthma-COPD overlap (ACO) is still controversial, the clinical characteristics of the patient’s disorders help inform their diagnosis and if the asthma or the COPD should carry more weight in treating the ACO. Recently, a low-dose ICS treatment has been considered the correct first-line therapy in ACO patients. A number of novel inhalers have been investigated and studied for this type of treatment. This review provides a summary of modern therapeutic approaches towards ACO and the current inhaled bronchodilators and glucocorticoids used in the therapy of asthma, COPD, and ACO.