The objective of this open-label multicentric study is to determine the adrenal suppression potential and the pharmacokinetic (PK) properties of halobetasol lotion (HBP) applied twice daily for up to two weeks in subjects aged 12 to 16 years 11 months with stable plaque psoriasis. Subject enrollment will continue until at least 20 subjects with both screening and end of study (EOS) serum cortisol data (pre- and pos-tcosyntropin stimulation) have completed the study without any significant protocol violations (evaluable subjects). This may require the enrollment of approximately 25 subjects.