This paper investigates the non-Markovian quantum Mpemba effect (NMQMpE), where a quantum system initialized in a steady state can relax to equilibrium faster than a state closer to equilibrium. The study focuses on general non-Markovian open quantum systems, revealing new classes of quantum Mpemba effects that do not exist in Markovian dynamics. The key findings include the existence of initial states that relax to the steady state within the finite memory time of the system, leading to the fastest possible relaxation to stationarity. The NMQMpE is demonstrated for quantum dot systems coupled to electronic reservoirs in both equilibrium and non-equilibrium setups, across weak, intermediate, and strong coupling regimes, with and without interactions. The analysis shows that non-Markovian dynamics allow for faster relaxation due to the finite memory time and unique steady state of open quantum systems. The study also identifies three types of NMQMpE: weak, strong, and extreme, with the extreme case involving an initial state that converges to the steady state within the memory time. The results are supported by numerical simulations for single and double quantum dots, showing the robustness of the NMQMpE across different parameters. The findings have implications for quantum control, quantum state preparation, and quantum thermal machines, highlighting the potential of non-Markovian dynamics in accelerating relaxation processes in quantum systems.This paper investigates the non-Markovian quantum Mpemba effect (NMQMpE), where a quantum system initialized in a steady state can relax to equilibrium faster than a state closer to equilibrium. The study focuses on general non-Markovian open quantum systems, revealing new classes of quantum Mpemba effects that do not exist in Markovian dynamics. The key findings include the existence of initial states that relax to the steady state within the finite memory time of the system, leading to the fastest possible relaxation to stationarity. The NMQMpE is demonstrated for quantum dot systems coupled to electronic reservoirs in both equilibrium and non-equilibrium setups, across weak, intermediate, and strong coupling regimes, with and without interactions. The analysis shows that non-Markovian dynamics allow for faster relaxation due to the finite memory time and unique steady state of open quantum systems. The study also identifies three types of NMQMpE: weak, strong, and extreme, with the extreme case involving an initial state that converges to the steady state within the memory time. The results are supported by numerical simulations for single and double quantum dots, showing the robustness of the NMQMpE across different parameters. The findings have implications for quantum control, quantum state preparation, and quantum thermal machines, highlighting the potential of non-Markovian dynamics in accelerating relaxation processes in quantum systems.