Background Some have hypothesized that changing attitudes toward medical aid in dying (MAID) contribute to increased suicide rates, perhaps by increasing interest in dying or the perceived acceptability of suicide. This would represent a strong criticism of MAID policies. We sought to evaluate the association between the legalization and implementation of MAID across the U.S. and changing suicide rates.Methods We evaluated state-level monthly suicide death rates from 1995 to 2021. Because suicide rates vary by state, we constructed geographically-weighted regression models (...) controlling for annualized state-level sociodemographic factors, such as racial distribution (percent Caucasian), average age, income levels, unemployment rates, rates of spiritual engagement, firearm ownership rates, gender ratios, and education levels. We applied a difference-in-difference analysis within our geographically-weighted models.Results 927,929 Suicide deaths were represented in the study. Ten states and the District of Columbia had legalized MAID within the study period. In an univariable analysis, states that legalized MAID differed significantly from non-MAID states with respect to mean monthly suicide rate (non-MAID States: 1.46; MAID states: 1.78; p < 0.0001), as well as several covariates. Monthly suicide death rates were spatially autocorrelated (Moran’s I = 0.607, p < 0.0001). In separate geographically-weighted difference-in-difference analyses, changes in suicide rates were not significantly associated with MAID legalization (β = 0.042, p = 0.33) or with later MAID implementation (β = 0.030, p = 0.63), with differences in suicide rates in MAID and non-MAID states being attributable to baseline between-state differences.Conclusions Our study failed to find evidence that suicide rates were positively associated with MAID legalization or MAID implementation, when controlling for geographic variation and multiple sociodemographic factors associated with suicide risk. This finding contrasts with other studies that have reported a positive association between suicide rates and MAID, and so calls into question one argument against MAID legalization. (shrink)