Three turbot groups were kept at 15℃ – 16℃ (Cold Temperature, T), 17℃ – 18℃ (ambient T) and 21℃ – 22℃(warm T) during the larval development in order to study the thermal influence on muscle growth and larval development in this species. During the early stages (2 – 6 days of post-hatching), the body and the muscle growth was scarce, although the hyperplasia increased slightly, being higher at ambient and at cold T than at warm T. In contrast, the highest value of hypertrophy was found in the warm group. At 15 days of age, the body length and muscle growth increased in all the groups, being significantly higher in the warm than in the rest of groups. Thus, the highest values of both the hypertrophy and the hyperplasia of the white muscle fibres were reached at warm T, although it was only significant for the hyperplasia. The end of the metamorphosis was reached at 29 days of age in the warm group, whereas in the rest of groups it was no observed yet. At this developmental stage, the warm group showed the typical morphological mosaic of the myotome, and it was accompanied by an increase of the transverse area of the white and the red muscles, parallel to an increase of both the hypertrophy and the hyperplasia of the muscle fibres. The hyperplasia of the white fibres was the parameter most significantly increased. Also, the body length increased significantly in this group, reaching ≈ 1.6 cm at this stage.