Terminal fusions—fusions of skeletal elements thought to mark the cessation of significant growth—can be used to estimate the relative maturity of fossilized individuals. Little is known of how the absolute timing of terminal fusions relates to sexual and skeletal maturity in squamates. Examination of postnatal ontogenetic series of extant representatives of 14 crown squamate clades reveals that no terminal fusion universally coincides with the achievement of either sexually or skeletally mature size; however, certain fusions may serve as benchmarks of maturity within particular crown clades. Complete fusion of the braincase is a reliable benchmark for skeletal maturity in scleroglossans, but not iguanians. Complete fusion of long bone epiphyses will indicate that a squamate individual is within roughly 20% of maximum size, whereas complete fusion of the scapula and coracoid, the pelvis, and the astragalus and calcaneum can be taken as evidence only that an individual has achieved at least half of the maximum size of its species.