There are currently over 6.2 million people with Alzheimer’s Disease and Related Dementias (ADRD) in the US and this population will grow to over 13 million by 2060. Patients with ADRD have high rates of health care utilization due to their complex health needs, which may have been impacted by the COVID-19 pandemic.This dissertation examined the patterns of health care utilization during COVID-19 for the ADRD population. I used 2019-2020 claims data from Inovalon MORE2 to identify emergency department (ED) visits, preventable ED visits, hospitalizations, potentially preventable hospitalizations (PPH), office/clinic visits, and telehealth visits and the Fall 2020 and Winter 2021 Medicare Current Beneficiary Survey COVID-19 Supplements to study telehealth access before and during COVID-19 and telehealth use during COVID-19. The first aim examined patterns in health care utilization before and during COVID-19 using an interrupted time series analysis. The results showed that the total number of ED visits decreased while the percent of preventable ED visits stayed the same, the total number of hospitalizations and the percent of PPH decreased, and office/clinic visits decreased while the percent of telehealth visits increased during COVID-19 for patients with ADRD. The second aim examined the impact of COVID-19 on the rate of monthly PPH for Managed Medicaid enrollees with ADRD and Medicaid expansion status using a difference-in-differences design. The results showed that COVID-19 did not affect the rate of PPH for patients with ADRD by state Medicaid expansion status. The third aim evaluated telehealth access and use for Medicare enrollees with a focus on enrollees with ADRD and Medicare Advantage within the context of COVID-19. Medicare enrollees with ADRD did not have different rates of telehealth access before or during COVID-19 or telehealth use during COVID-19 compared to their non-ADRD counterparts. The interaction of Medicare Advantage and ADRD was not significant in rates of telehealth access or use. Findings from this dissertation provide policymakers with evidence on how to predict and prepare for the health care needs of future pandemics for vulnerable populations such as patients with ADRD.