The population of older adults is growing worldwide, particularly in North America. Health information technology (HIT) is a group of technologies and systems that enhance care by electronically storing, managing, and exchanging data. HIT presents opportunities to support older adults' healthcare needs in communities and long-term care (LTC) environments. Despite their potential benefits, these technologies remain limited in LTC and older adults' healthcare contexts. Evidence is scattered on the factors that affect older adults' adoption of HIT. Little research has investigated the adoption of these technologies by formal healthcare providers and the technologies' impacts on LTC. A multi-method approach was employed in this thesis research, using a combination of a systematic qualitative review, an inductive semi-qualitative Delphi survey, and a quantitative deductive study to manage each research question in order to address these gaps. The systematic literature review used the PRISMA guidelines to identify and critically appraise studies that examined the effect of various HIT adoption factors among older adults in the community. The search involved five databases and a combination of keywords, resulting in the selection of critically appraised articles based on their evidence level and research rigor. A coding scheme was developed to extract information from the selected articles. The results showed that the main factors affecting HIT adoption by older adults relate to performance expectancy, effort expectancy, and high price/cost value. It also highlighted the importance of considering privacy/security and product design when evaluating HIT adoption by older adults. In light of the limited available studies on HIT adoption and impacts in the context of LTC, a Delphi study was developed to collect data from key formal healthcare providers (i.e., nurses) working in LTC at one of the largest and most progressive older adult healthcare facilities in Ontario, Canada. The Delphi study aimed to identify and prioritize the key factors that affect nurses' adoption of new technologies in support of older adults' care. A panel of nurses was solicited to participate in the Delphi study, which involved three rounds of data collection: brainstorming, narrowing down, and ranking. A total of 20 nurses completed the Delphi study, and the top factors that the LTC nurses identified were mainly related to the organizational and technological dimensions, including the complexity of HIT, the training and support provided, the interoperability of HIT systems, the cost of implementation, and the availability of HIT infrastructure. For the last part of this research, quantitative secondary data analysis was conducted on a Canadian national survey of nurses to examine their perceived impacts of HIT adoption by nurses in LTC. The survey included questions related to the current state of electronic medical records (EMR) and EMR adoption, the state of virtual care technologies, attitudes and perceptions related to access and the impact of the adoption of digital health technologies in practice, benefits and effects of EMR adoption, and barriers preventing nurses from getting total value from electronic health. A subset of 166 nursing homes/long-term care facilities/older adult residences and homecare nurses were selected for this analysis. Data management and analysis were conducted using IBM SPSS v28. The results showed that HIT adoption by nurses in LTC was positively associated with perceived benefits and organizational support. However, HIT adoption was negatively associated with perceived complexity and privacy/security concerns. This thesis research suggests that HIT adoption by older adults and nurses in LTC is complex and multifaceted, requiring attention to individual, organizational, and technological factors. There is a need for improved communication and collaboration among LTC team members and better working conditions to improve staff well-being and reduce turnover. The findings from the systematic review and Delphi study contribute to the theoretical understanding of the factors influencing the adoption of HIT in LTC facilities. The survey results provide valuable insights into the current state of HIT use in LTC facilities and can be used to inform the development of targeted interventions to improve HIT adoption and use. Overall, this study contributes to the growing body of knowledge on HIT adoption in LTC facilities and provides important recommendations for policymakers, administrators, and LTC staff to improve the use of HIT and ultimately enhance the quality of the care supplied to LTC residents.