The objectives of this study were twofold: to develop and psychometrically test a questionnaire to measure health profession students’ knowledge of aging in older adults and to assess comparative professional geriatric knowledge in pharmacy, nursing, and physician assistant (PA) students.An interdisciplinary team of faculty with clinical geriatric expertise and experience in item scale development designed a scale, termed the Geriatric Knowledge Assessment Scale (GKAS), to measure health profession students’ geriatric knowledge in the areas of aging disease, physical activity, drug therapy, and nutrition. Upon development of the scale, the psychometric properties of the GKAS were analyzed. The tool was administered to pharmacy, nursing, and PA students in the final semester of their professional education programs.A total of 412 students participated in the test and 408 completed the questionnaire with health profession responses as follows: pharmacy students (n = 159), nursing students (n = 162), and PA students (n = 87). PA students scored at a significantly higher level on the GKAS than both pharmacy and nursing students (p < 0.001), and pharmacy students scored significantly higher than nursing students (p = 0.05). Overall, 65% of students agreed or strongly agreed on a five-point Likert scale that the gerontological content in their professional education adequately prepared them to address the health care needs of older adults.Further research and utilization of the GKAS in geriatric health care education is required. Our findings also support ongoing evaluation of geriatrics education and training within all health professions.