To document trends in inequity in homicide rates in Mexico for the period 2000–2021, at the state and national levels.
An observational, longitudinal ecological study was conducted in which standardized homicide mortality rates were estimated, by municipality and sex. Municipalities were classified in five groups, according to the Social Lag Index. The absolute inequality gap was obtained, as well as differences between groups with very high and very low social lag, for each year of the study period.
In the 32 states, an increase was observed in the rate of death by homicide, with higher rates among men but a greater relative increase among women (+127.86% vs. +110.03%). The absolute gap between municipalities with very high and very low social lag narrowed in the period, due to higher homicide rates in municipalities with low social lag and a modest reduction in municipalities with very high social lag.
In Mexico, between 2000 and 2021, the absolute gap in deaths by homicide between municipalities with very high and very low social lag declined due to higher homicide rates in municipalities with lower social lag. It is necessary to strengthen policies and actions aimed at addressing the social determinants of interpersonal violence.