The Simple Copy Task (SCT) is a figure copying test with inherent appeal due to its short administration time, graded task difficulty, varied stimuli, and potential to eliminate floor effects. Despite this, there is a lack of data regarding its construct validity and diagnostic utility. The present study compared SCT performance of schizophrenia (n = 29), dementia (n = 64), and movement disorder (n = 12) groups with that of unmatched healthy control participants (n = 49). Movement disorder patients committed a high degree of misplacement errors, whereas dementia patients tended to omit items, add extraneous detail, and perseverate. The schizophrenia group was most similar to the dementia group in their performance on the SCT, committing primarily omission and perseveration errors. The SCT was most closely related to the Rey Complex Figure Task (r = 0.68, p < .01) and the Block Design Task (r = 0.62, p < .01). Age (r = −0.14, p < .01) and education (r = 0.35, p < .01) effects were present; however, there was no impact of gender and handedness. Taken together, these findings provide support for the utility of the task and directions for clinical interpretation.