Seasonal upwelling in the coastal waters of the Gulf of Guinea is unusual because classical coastal upwelling theory does not even qualitatively hold there; there is no significant relationship between the upwelling and the local longshore wind stress. In this paper an attempt is made to qualitatively explain the Gulf of Guinea seasonal upwelling using coastal trapped forced wave dynamics. Two independent sets of data were used to compare theory with observation. Both indicate that provided dissipation of the travelling wind-forced wave is taken into account, the theory agrees qualitatively with observation. The implication is that the upwelling is generated by coastal wind forcing several hundred kilometers east of the upwelling region. The Gulf of Guinea coastal upwelling therefore does not seem to be related to upwelling generated along the equator or to deep ocean basin forcing-it is not an 'anti El Ni¿o,' as has been postulated elsewhere.