Purpose: Bilingual proficiency may be one of the contributing factors to cognitive reserve, and bilingual experience appears to influence not only language itself but also general cognitive functions and the neural networks that support both language and cognition. In older adults, semantic networks tend to be smaller, have lower semantic associations, higher density, and deviate from small-world characteristics. Analyzing the structural features of semantic networks may help describe and predict cognitive performance in aging populations and distinguish between normal and pathological aging. This study employed semantic network analysis to examine differences in cognitive reserve between bilingual and monolingual older adults. It was hypothesized that bilingualism has a positive impact on cognitive reserve in later life. Methods: A total of 200 community-dwelling older adults aged 65 and above were recruited from central and southern Taiwan. Using a quasi-experimental design (non-randomized between-subjects variable: bilingual vs. monolingual), participants completed the Cognitive Reserve Index questionnaire (CRIq), the Mini-Mental State Examination (MMSE), and the Montreal Cognitive Assessment (MoCA) to assess their cognitive function. During testing, a Semantic Fluency Test was also administered to collect semantic network data, which was analyzed using Snafu software. Hierarchical multiple regression analysis was conducted to test the study hypotheses. Results: Bilingual older adults outperformed monolingual peers in cognitive function measures (MoCA, MMSE) and showed higher cognitive reserve scores (CRIq). Their semantic networks also resembled those of individuals with higher cognitive reserve—characterized by a greater number of nodes, higher average node degree (semantic association), and lower network density. Conclusion: Findings suggest that bilingual experience positively contributes to cognitive reserve in older adults. Bilingualism may enhance cognitive functioning and help delay age-related cognitive decline.