We have performed resonant interband transmission spectroscopy on the transitions between the s -shells and the p -shells of a single charge tunable InGaAs quantum dot (QD). In contrast to the s -shell spectroscopy, investigating p -shell transitions allows the study of a QD charged with up to four electrons. The exciton charging state is clearly identified as a function of gate voltage ranges. In contrast to the s -shell, the p -shell electronic states show a strong tunnel coupling to the Fermi sea of the back contact. © 2008 American Institute of Physics.