Empowerment as a crucial element of health promotion has increasingly been prioritized among people who are capable of raising their voice and having a meaningful input in their care. The “Youth Efficacy/Empowerment Scale-Mental health” (YES-MH) is a measure designed to evaluate empowerment from the perspective of young service users living with mental health problems. The present study aimed to examine the psychometric properties of the YES-MH among youth clinical population in Greece and secondarily to analyze the relationship between empowerment and socio-demographic variables. Data were collected in mental health care settings of Athens from 150 participants aged 12 to 17 years. Exploratory factor analysis was conducted by the method of Principal Components to determine the structure. Validity was tested by comparing the YES-MH with two scales and reliability by using Cronbach alpha coefficient. Results indicated the predicted three-factor solution and acceptable internal consistency (0.76 to 0.86). Concerning the concurrent validity, YES-MH significantly correlated with mental well-being (r = 0.60) and the presence of difficulties (r = −0.34)”. Moreover, empowerment was associated to gender and family economic status at the self-level and significantly higher scores were observed to the younger. The current study added evidence for the validity and reliability of the Greek version. Its implications extend from research to practice including the evaluation of interventions and the improvement of services.