Postural tachycardia syndrome (POTS) is a chronic form of orthostatic intolerance associated with cognitive dysfunction. We hypothesized executive function and attention is impaired in POTS during active standing. Eighty-seven POTS participants and 39 healthy controls of similar age, sex, and education level completed executive function (Stroop word-color) and attention (CogState Identification) tests in supine and standing postures in a cross-sectional study. POTS participants had lower executive function (t-score: 48 ± 11 vs. 55 ± 10 control; p = 0.009) and worse attention (reaction speed: 2.78 ± 0.11 vs. 2.69 ± 0.06 control; p < 0.001) during standing. These data provide new evidence that active standing impairs attention and executive functioning in POTS.