This study examined the psychological mechanisms of effort justification and the extravagance effect in driving costly wedding expenditures and analyzed their socio-economic implications for individuals, families, and communities in Uganda. Employing a mixed-methods design, the research collected data from 450 participants in Kampala and Wakiso districts through structured questionnaires and 30 semi-structured interviews with recently married couples, parents, and wedding vendors. Quantitative analysis included univariate descriptive statistics, bivariate correlations and chi-square tests, and structural equation modeling to test the hypothesized theoretical framework. Results revealed that Ugandan couples spent an average of UGX 28.6 million on weddings—equivalent to 15.5 months of household income—with 76% incurring post-wedding debt averaging UGX 15.3 million requiring 31.4 months to repay. Social pressure emerged as the strongest predictor of wedding expenditure (β=0.384), followed by effort justification (β=0.297) and extravagance effect (β=0.263), collectively explaining 62.3% of spending variance, while household income contributed minimally (β=0.112). The structural equation model demonstrated excellent fit (CFI=0.961, RMSEA=0.039) and revealed that cultural expectations strongly influenced social pressure (β=0.634), which then activated psychological mechanisms that mediated the relationship between social norms and individual spending decisions. Wedding expenditure showed a near one-to-one relationship with subsequent debt (β=0.731), which powerfully predicted financial strain (β=0.682). Significantly, 59.3% of couples delayed home purchases, 52% reduced business investments, and 42% postponed further education due to wedding-related financial constraints, demonstrating substantial opportunity costs. The regressive nature of financial impacts—with lower-income households experiencing disproportionate debt burdens—highlighted how wedding expenditure perpetuates economic vulnerability among aspirational middle-class families. Qualitative findings revealed that social pressure operated through fear of community judgment, family reputation concerns, and status signaling motivations, while effort justification manifested in couples' post-hoc rationalization that expensive celebrations were "investments" in their marriage or family honor. The study concluded that wedding expenditure in Uganda represents a culturally-embedded practice where social norms override economic rationality through psychological mechanisms, creating predictable patterns of debt accumulation and financial hardship. Recommendations included community-level interventions to reshape social norms, mandatory pre-wedding financial counseling, responsible lending standards, and educational programs targeting the psychological mechanisms that sustain excessive spending, emphasizing the need for multilevel approaches that address cultural, social, psychological, and economic dimensions of this complex phenomenon.