The transfer of a chemically reactive species in laminar viscous flow over a linearly stretching sheet is considered, and a similarity transformation is applied to reduce the equations governing the flow and concentration field to coupled nonlinear differential equations. Different from perturbation techniques, however, and based on a newly developed analytical method, namely homotopy analysis method (HAM), an approximate analytical solution to the concentration boundary layer problem in the presence of a chemically reactive species is given. Comparisons are also made between the present results and those of previous work and numerical methods as well, which verify the validity of the provided analytical solution. The influences of reaction-rate parameter on the concentration distribution are further analytically shown in the presence of first- and second-order chemical reaction. The analytical solution can be conveniently applied to gain results that will help to understand the transfer mechanism of a chemically reactive species in laminar viscous flow over a linearly stretching sheet.