We construct the relativistic chiral Lagrangians for heavy-light mesons (Qq) to the O(p 4 ) order. From O(p 2 ) to O(p 4 ), there are 17, 67, and 404 independent terms in the flavor SU (2) case and 20, 84, and 655 independent terms in the flavor SU (3) case. The Lagrangians in the heavy quark limit are also obtained. From O(p 2 ) to O(p 4 ), there are 7, 25, and 136 independent terms in the flavor SU (2) case and 8, 33, and 212 independent terms in the flavor SU (3) case. The relations between low-energy constants based on the heavy quark symmetry are also given up to the O