Differences in the ultrastructure and function of the mandibular glands in developing workers and mature males of the meliponine stingless bee Scaptotrigona postica suggest that there are age-dependent variations in the contents of the secretion and glandular functions. In this work, we used transmission (TEM) and scanning (SEM) electron microscopy to examine the mandibular glands of S. postica workers of different ages and compared them with those of mature males. The gland anatomy did not vary between workers and males. However, the ultrastructure of the gland cells changed according to the worker’s age, task, and sex. The mandibular gland cells in workers and males had a well developed smooth endoplasmic reticulum and pleomorphic mitochondria, indicating that the cells were involved in lipid synthesis. However, the secretion varied in morphology and electrondensity between workers and males, which suggested differences in its contents and, possibly, in glandular functions.