This study investigated the validity and reliability of the Turkish version of the Depression Anxiety Stress Scale (DASS). The sample of the study consisted of 590 university students, 121 English teachers and 136 emotionally disturbed individuals who sought treatment in various clinics and counseling centers. Factor loadings of the scale ranged from .39 to .88. Findings from discriminant validity showed that the DASS discriminates the normal and clinical population. Concurrent validity coefficients were found to be high (.87 and .84, respectively). Cronbach internal consistency of the entire scale was .89. Item-total correlations ranged from .51 to .75. Test-retest and split-half reliability coefficient scores were .99 and .96 respectively. These results demonstrate that the DASS is a valid and reliable instrument.