A sheet feeding apparatus capable of reliably feeding a sheet even when a gap is formed between the sheet and a regulating portion, and an image forming apparatus are provided. A tail end regulating plate 13 regulates a movement of a sheet supported by a tray supporting the sheet so as to be lifted or lowered, and when a gap is formed between the tail end regulating plate 13 and the sheet supported by the tray, tail end regulating projections 18H and 18I which are provided so as to protrude to the gap regulate the movement of the sheet toward the tail end regulating plate 13.