An estimated 6 million adults aged 60 and over in the United States have Alzheimer’s disease and related dementias (AD/ADRD) at a cost of $345 billion per year. Older adults with mild cognitive impairment (MCI), an intermediate stage between typical aging and dementia, are 3-5 times more likely to progress to AD than those with normal cognition. Although new pharmacological interventions for dementia appear to slow disease progression by about 6 months, they do not cure the disease or improve quality of life, and are often contraindicated or discontinued due to significant side effects. Thus, there is a compelling need to continue testing non-pharmacological alternatives for slowing disease progression. Late-life engagement in cognitively challenging activities has been associated with decreased risk of cognitive decline; however, not all older adults, particularly those with MCI, remain cognitively active. Music-based interventions (MBIs) are a promising strategy for addressing cognitive inactivity in late-life. Group singing, in particular, is an appealing approach because it is a multi-domain process that involves the complex interplay of numerous brain regions. Research has shown that group singing facilitates social bonding and benefits health and cognition in community- dwelling elders as well as in patients with dementia. However, few studies to date have investigated the effects of group singing for older adults with MCI. Because internet-based interventions can improve quality of life and decrease social isolation and depression in older adults, including older adults with MCI, the proposed project will develop, refine, and test the effects of an online group singing intervention for older adults with MCI in two phases. In Phase 1, we will develop and refine an online group singing intervention that uses the JackTripTM Virtual Studio, a platform that provides an audio-visual setup similar to Zoom but with minimal latency delays allow singers to achieve the “same room” experience. We will aim to test the feasibility of the MBI Toolkit principles and affect all three Science of Behavior Change (SOBC) targets (i.e., interpersonal and social processes, stress reactivity, and self-regulation) with the intervention. In Phase 2, we will conduct a 2-arm randomized pilot trial to examine the feasibility and acceptability of the online group singing intervention versus an attention control condition according to the NIH MBI Toolkit principles and guidelines. We will also examine the feasibility of administering the assessments of the proposed SOBC targets of our online group singing intervention. The successful completion of this study will support a subsequent, larger randomized effectiveness trial that will rigorously evaluate our online group singing intervention versus an active attention control as a viable intervention for MCI and other brain disorders of aging.