Variation in height among young adults has been linked to the living conditions of different social groups. The aim of this study was to measure variation in the height and knee height of young adults by head of household employment level and family income. The sample comprised 180 individuals (90 girls) aged 16 and 17 years living in the city of Merida, Mexico. Height and knee height were measured by anthropometry, and individuals' family social and economic data collected from their mothers. Variation in these measurements was analysed by three categories of employment and family income terciles. One-way ANOVAs were done by sex to compare mean height and knee height by employment and family income. Coefficients of variation were calculated and a Bartlett test applied. Significant differences in height and knee height were observed only between family income terciles. Both sexes were taller at the highest levels of family income (p<0.05) and men had the highest (p<0.05) knee height. Highest family income individuals exhibited the least variation in height and knee height. Similarity in socioeconomic conditions for families in the lowest family income tercile and with employee heads of household was not associated with lower variation of height and knee height.