Zonal wave number frequency spectra of surface temperature (ST) and sea level pressure (SLP) anomalies extending around the global tropical ocean at 10¿N from 1950 to 1997 display significant peaks for 2.0 and 2.4 year periods, dominated by eastward propagating zonal wave numbers of global scale. Applying complex principal component analysis to quasi-biennial ST, SLP, and surface wind (SW) anomalies for 25 years from 1973 to 1997 separates this global quasi-biennial wave (GBW) from corresponding global standing modes, with patterns and evolution of the former similar to those observed in the global El Ni¿o-Southern Oscillation wave but centered on the equatorial waveguide and taking only 3 to 4 years (instead of 4 to 6 years) to transit the global tropical ocean at 0.30 to 0.40 m s-1. We find the GBW contributing to the quasi-biennial signal in Ni¿o-3 ST and SLP indices with amplitude twice that of global standing mode. In the GBW the ocean forces the atmosphere with SW anomalies directed toward warm sea surface temperature anomalies, while the atmosphere forces the ocean with SW-induced Kelvin waves on the equator and SW-induced sensible-plus-latent heat flux and/or vertical mixing anomalies elsewhere, both advancing ST anomalies eastward. Examining the GBW from 1900 to 1994 finds its amplitude modulated by the decadal signal of ~10 year periodicity, robust (weak) when tropical temperature gradients and trade winds were stronger (weaker) than normal. ¿ 2001 American Geophysical Union