The effect of turbulent friction on transient three-dimensional wind-driven circulation in large lakes is studied. Horizontal friction is neglected, and vertical friction is modeled by a constant eddy viscosity. The linearized Ekman equations are used in a constant depth lake model which is assumed deep (of small Ekman number). High-frequency transients due to acoustic, internal, and surface gravity wave modes are eliminated through assumptins of incompressibility, homogeneity, and rigid lid surface, respectively. The initial value problem arising from a suddenly imposed wind stress on an initially quiescent lake is analytically solved, and significant time scales are identified. It is found that the manner in which transient currents adjust to temporal variations in wind stress depends not only on a lake's physical parameters but also on the wind stress spatial pattern. While the inerital period is always significant, the spin-up time is significant only when the wind stress has a nonzero curl.