Sexual maturity is an important phase of brachyuran's life cycle as it marks the transition of becoming an adult and the ability to reproduce. This article discussed on the types of sexual maturity found in brachyurans and the implication and application of size at the onset of sexual maturity (SOM) in general. In addition, data on the estimates of SOM of brachyurans were collected on a global scale for the period 1971–2015. The 220 maturity data were representative of 133 brachyuran stocks from 23 families and 55 species. The effect of sampling methods and indicators used for the estimation of SOM were highlighted as well. Variation in the carapace width at which 50% of the population reaches maturity (CW₅₀) was apparent between families, species, sexes, and populations within the same species, in addition to latitudinal and temporal variation. The CW₅₀ was in a positive linear relationship with the maximum size (CW_max) for males (logCW₅₀ = -0.28 1.01logCW_max; R² = 0.85, P < 0.001), females (logCW₅₀ = -0.35 1.08logCW_max; R² = 0.96, P < 0.001), and specifically Portunidae (logCW₅₀ =-0.88 1.32logCW_max; R² = 0.69, P < 0.001). The size at maturity data in this review serve as guidelines for stock assessment and sustainable population management of brachyuran species.