§1. Clerics are obliged to carry out the liturgy of the hours according to the norm of can. 276, §2, n. 3; members of institutes of consecrated life and societies of apostolic life, however, are bound according to the norm of their constitutions.
§2. Other members of the Christian faithful, according to circumstances, are also earnestly invited to participate in the liturgy of the hours as an action of the Church.
Source: Code of Canon Law (Vatican.va)