Abstract: Star formation rate (SFR) is one of the fundamental parameters that defines galaxies and their evolution across cosmic time. Although multi-wavelength SFR diagnostics have been extensively studied in nearby galaxies, high-redshift galaxies have intrinsic physical differences that may affect the level of accuracy of the local calibrations. In this talk, I will review our recent findings on some of the most commonly-used SFR indicators at high redshifts, namely stellar UV continuum, nebular emission lines, and mid- and far-IR dust emission. In the process of studying the SFR diagnostics, we will gain valuable insights on the stellar and dust conditions in high redshift galaxies and how they evolve with cosmic time.