This study aimed to investigate the relation of adherence to the planetary diet with food and nutrition security status and per capita household income in a study with a representative sample of the Brazilian population. Among the data from the 2017-2018 Brazilian Household Budgets Survey (POF), the inequality indicators selected for the analysis were data on per capita household income and food and nutrition security. We also considered data on the individual food consumption of 46,164 Brazilians aged ≥ 10 years, obtained through 24-hour dietary recalls, in the National Food Survey, conducted with the POF 2017-2018. The Planetary Health Diet Index (PHDI) was used to measure adherence to the planetary diet. Sociodemographic data were expressed as frequency (%), with analysis of the mean and 95% confidence interval (95%CI) of the PHDI score. The relation of food and nutrition security and income with the PHDI score was tested in multiple linear regression models. The calculations were performed in the Stata software, adopting a 5% significance. Lower PHDI means were observed among food insecure individuals, male, < 20 years old, mixed-race and indigenous, with income < 0.5 minimum wage, residing in rural areas and in the North and Northeast regions. In the multiple linear regression, food insecurity was inversely related to PHDI score (ꞵ = -0.56; 95%CI: -1.06; -0.06), with the lowest scores associated with severe food insecurity (β = -1.31; 95%CI: -2.19; -0.55). Income categories were not independently associated to PHDI score (p-trend = 0.900). Therefore, food insecurity has been shown to negatively affect Brazilians' adherence to the planetary diet.