  We construct a quantum Markovian Master equation for a driven system coupled
to a thermal bath. The derivation utilizes an explicit solution of the
propagator of the driven system. This enables the validity of the Master
equation to be extended beyond the adiabatic limit. The Non-Adiabatic Master
Equation (NAME) is derived employing the weak system-bath coupling limit. The
NAME is valid when a separation of timescales exists between the bath dynamics
and the external driving. In contrast to the adiabatic Master equation, the
NAME leads to coupled equations of motion for the population and coherence. We
employ the NAME to solve the example of an open driven time-dependent harmonic
oscillator. For the harmonic oscillator the NAME predicts the emergence of
coherence associated with the dissipation term. As a result of the
non-adiabatic driving the thermalization rate is suppressed. The solution is
compared with both numerical calculations and the adiabatic Master equation.
