Asthma control is recognized as a critical aspect of the evaluation and management of the disease. Here we evaluate and compare existing instruments for measuring asthma control in an attempt to evaluate their clinical utility. Based on a literature review, we identified validated instruments used to assess asthma control in adults. We examined the specific measurement properties and the strengths and weaknesses of each instrument, and evaluated a single instrument, the Asthma Control Questionnaire (ACQ), more closely as an example, evaluating its applicability in the clinical setting. Our review identified five validated instruments designed to measure asthma control: the Asthma Control Questionnaire (ACQ), Asthma Control Scoring System (ACSS), Asthma Control Test (ACT), Asthma Therapy Assessment Questionnaire (ATAQ), and the Lara Asthma Symptom Scale (LASS). None of the instruments covered all relevant control characteristics, but most were aligned with guideline definitions of control. All instruments demonstrated validity and responsiveness, with some measure of reliability. All instruments were short and easily administered, easy to interpret, and all had evidence to support their use in clinical decision making.