ABSTRACT Background: As older adults transition to nursing homes from the community, their health and quality of life in nursing homes are significantly influenced by various factors, including family involvement in care planning. Family involvement is associated with better health outcomes in older adults, yet its impact on specific conditions like therapy administration, depression, and pressure injuries among nursing home residents remains understudied. This dissertation addresses these gaps by examining the role of family involvement in these key areas. Methods: Using national data from the Minimum Data Set (MDS) 3.0, this dissertation explores the influence of family involvement on nursing home care and health outcomes from 2014 to 2019. The study includes three aims: 1) assessing the association between family involvement and rehabilitative therapy administration among newly admitted residents transferred from acute care in 2019; 2) examining the relationship between perceived family involvement and changes in depression severity in long-stay residents from 2014 to 2019, and 3) evaluating the impact of family involvement on the risk of developing stage 2 or higher pressure injuries in long-term care residents from 2014 to 2019. Statistical methods included linear regression, Poisson regression, and generalized estimating equations (GEEs). Results: The first study included 2,112,330 residents aged 50 years and older. In Aim 1, residents who reported family involvement as "Very Important" received an average of 247 minutes of individual physical therapy and 236 minutes of individual occupational therapy, compared to 222 minutes of individual physical therapy and 215 minutes of individual occupational therapy among those who found it "Important, but no choice." Adjusted analyses showed that residents who rated family involvement as "Not Important at All" received 21 fewer therapy minutes (95% CI: -27, -15) compared to those who valued it as "Very Important." In Aim 2, among 2,043,308 long-stay nursing home residents, those with none-to-low baseline depression who perceived family involvement as "Not Important at All" had a 10% higher risk of significant worsening of depression symptoms (RR: 1.10, 95% CI: 1.06, 1.14) after adjusting for confounders, compared to those who considered it "Very Important." Conversely, among residents with moderate to moderately severe baseline depression, those who perceived family involvement as "Not Important at All" had a 33% higher risk of significant worsening (RR: 1.33, 95% CI: 1.10, 1.61) compared to the "Very Important" group, after adjusting for covariates. In Aim 3, among 579,958 residents, the relative risk of developing stage 2 or higher-pressure injuries was 0.97 (95% CI: 0.78, 1.22) for those who rated family involvement as "Not Important at All," compared to those who viewed it as "Very Important." Subgroup analysis revealed a higher risk for residents with severe physical impairments (RR: 1.34, 95% CI: 0.94, 1.93) and those with no urine output/ostomy (RR: 1.59, 95% CI: 0.88, 2.86). Conclusions: This dissertation underscores the significant role of family involvement in enhancing the care and health outcomes of nursing home residents. Higher family engagement is associated with increased rehabilitative therapy use, reduced risk of worsening depression, and nuanced effects on pressure injury development, particularly among vulnerable subgroups. These findings highlight the need for nursing homes to foster family involvement in care planning as a strategy to improve residents' overall health and well-being. Implementing policies that encourage family engagement could lead to more personalized and effective care, ultimately enhancing the quality of life for older adults in nursing homes.