A reclining chair having a seat, backrest and armrest is provided. The armrest has a first portion associated with the seat and a second portion associated with the backrest. The first and second armrest portions are slidable relative to each other between a first position associated with a raised backrest and a second position associated with a reclined configuration. The armrest also has a locking mechanism of the sliding between the first and second armrest portions, and the locking mechanism has first and second locking seats and a locking element configured to couple alternatively to the first-or to the second locking seat. A coupling of the locking element to the first locking seat is associated with the first position and a coupling of the locking element to the second locking seat is associated with the second position.