Acoustic wave devices have great potential for integration with lab-on-chip highly efficient microfluidics. This article investigates Lamb wave-based unidirectional transducers for application in acoustic wave-driven microfluidic devices with high efficiency. The simulation of the unidirectional transducer is performed via the finite element analysis. The optimal cell design of the transducer is suggested according to the Lamb wave uneven excitation. In particular, we propose a sophisticated double-side IDT pattern to enhance Lamb wave transduction. The anti-symmetric A0 mode implemented with double-side unidirectional transducers is determined and optimized for the microfluidic device application. The optimum Lamb wave-based devices are fabricated on a wafer of 128° YX LiNbO3 with a thickness of 300 [Formula: see text] using an elaborate two-side lithography technique. The amplitude of Lamb waves excited from the unidirectional transducers are measured and confirmed the unidirectionality, accordingly. Thorough atomization and jetting experiments driven by the unidirectional transducer are presented. The results agree with the simulation and verify the efficiency of the proposed double-side patterned unidirectional transducers in microfluidic applications.