Progressive transmission of images based on the lapped orthogonal transform (LOT), adaptive classification, and human visual sensitivity (HVS) weighting is proposed. HVS weighting for LOT basis functions is developed. This technique is quite general and can be applied to any orthogonal transform. The method is compared with discrete cosine transform (DCT)-based progressive image transmission (PIT). It is shown that LOT-based PIT yields subjectively improved images compared to those based on DCT. This is consistent with the reduction in block structure characteristic of LOT image coding.