In blind mole-rats, extensive chromosomal diversity despite pronounced morphological similarity indicates the presence of distinct evolutionary lineages, as supported by genetic evidence. Accordingly, analyses were restricted to a single cytotype (2n = 60) to minimize morphological heterogeneity associated with differences in diploid chromosome number. This study examined age- and sex-related mandibular shape variation in Nannospalax cilicicus using landmark-based geometric morphometrics (GM). A total of 120 individuals (20 males and 20 females per age class: subadult, adult, elderly) were analyzed. Mandibular size differed significantly among age groups, whereas no sexual size dimorphism was detected. In contrast, mandibular shape varied significantly with both age and sex. Sexual shape dimorphism was independent of size, absent in subadults, and became pronounced with maturation. After controlling for allometry, age-related shape differences persisted in males but not in females. Adult males exhibited a more robust mandibular configuration characterized by superoposterior expansion of the ramus and reinforcement of the basal contour, reflecting increased functional loading associated with digging. In contrast, elderly males displayed a more compact morphology, with lateral expansion of the anterior and basal regions and reduced ramus height, consistent with age-related remodeling. Female mandibles exhibited limited, non-directional shape variation across ontogeny, consistent with a more stable ontogenetic trajectory. This study provides the first GM assessment of ontogenetic and sexual mandibular shape variation conducted within a single cytotype in N. cilicicus, demonstrating that mandibular morphology is shaped by the interaction between ontogenetic stage and sex and that the observed sex-specific patterns are consistent with differential functional demands.