AIM: To synthesise evidence regarding the association between positive psychological constructs (PPCs) and cognitive function in adults aged 50+. METHODS: Literature searches: Medline, PsycINFO, and Scopus (inception to February 2022). Studies were included if they reported on the association between at least one PPC and one objective measure of cognitive function in people aged 50+ without cognitive impairment at baseline. Where at least two studies reported on the same PPC and cognitive outcome, estimates were pooled through meta-analysis. FINDINGS: In total, 37 studies were included. There was evidence of cross-sectional associations for 'meaning in life' (verbal fluency: b=0.09, 95%CI[0.07,0.11], p<.001; memory: b=0.10, 95%CI[0.08,0.12], p<.001), 'purpose in life' (verbal fluency: b=0.07, 95%CI[0.05,0.08], p<.001; memory: r=.13, 95%CI[0.08,0.18], p<.001), and positive affect (cognitive state: r=.25, 95%CI[0.14,0.36], p<.001; memory: r=.05, 95%CI[0.02,0.08], p<.001) with various domains of cognitive function. However, no significant results were found for life satisfaction (p=.13) or longitudinal studies investigating positive affect and memory (p=.48). Other PPCs were included in narrative syntheses only. IMPLICATIONS: Purpose and meaning in life may be sensible primary targets for interventions to promote healthy cognitive aging. More longitudinal and causal inference research is needed to better understand this association and its implications for clinical practice.