Pfeiffer syndrome (PS) (MIM 101600) is one of the most common syndromic forms of craniosynostosis. It is characterized by craniosysnostosis, midface hypoplasia, broad and medially deviated thumbs, and great toes with partial syndactyly of the digits. Here, we described clinical and genetic features of 12 unrelated Thai individuals with PS. All 12 patients were sporadic, and advanced paternal age was found in 50% of the cases. Polymerase chain reaction sequencing of FGFR1 exon 5 and FGFR2 exons 8, 10, 15, 16, and 17 was performed in all PS patients and revealed 9 recurrent mutations in all patients. Most of the mutations clustered in exons 8 and 10 (9/12) accounting for 75% of PS cases. The most frequently detected mutation, p.S351C, was associated with the severe form of PS in the Thai population. Less frequent mutations in exons 16 (p.K641R) and 17 (p.G663E) were also identified. In addition, the p.P252R mutation in FGFR1 was detected in 1 PS patient with unilateral coronal craniosynostosis expanding the phenotypic spectrum of PS with this particular mutation. Knowing the mutation spectrum of the responsible genes could lead to the most effective strategy in identifying mutations causing Pfeiffer syndrome in the Thai population.