This rapid review evaluates interventions aimed at improving life satisfaction and aids policymakers, researchers, and practitioners by identifying research strengths, gaps, and future directions for life satisfaction research. Intervention inclusion criteria were: use of a control group; delivered in high-income OECD country; randomised control trials or quasi-experimental studies; published between Jan 2011–Oct 2023; English language; uses a validated life satisfaction outcome measure. Of 9520 search results across five academic databases and grey literature sources, a total of 189 studies with 234 intervention arms met criteria for inclusion. The six themes (18 total subthemes) identified were: Emotion-based activities (intrapersonal and interpersonal, n = 154); Didactic emotional development (n = 30); Health promotion (n = 31); Social media (n = 4); Music (n = 3); and Multi-component interventions (n = 12). Meta-analyses were possible in six subthemes and examined overall standardised mean differences (SMD) in life satisfaction from pre-to post-intervention between the intervention and control group. The review primarily identified intrapersonal (related to self) emotional activities as generally associated with small improvements in life satisfaction: mindfulness (SMD: 0.28 (95% Confidence Interval: 0.13, 0.42)), gratitude (0.19 (0.11, 0.27)) and therapy (0.33 (0.12, 0.53)). Additionally, meta-analysis revealed a moderate effect of emotional skills development training (SMD 0.50 (0.12, 0.88)) and a small effect of exercise (SMD: 0.33 (0.04, 0.62)) on life satisfaction. Subthemes with mixed evidence (i.e., some interventions were effective while others were not) included: positivity and prosocial activities, emotional regulation and resilience training, health promotion education, ‘other’ intrapersonal emotion-based activities which could not otherwise be categorised, and multi-component interventions. The findings of this rapid review offer comprehensive insight into effective interventions for improving life satisfaction as well as areas for further research.