Intrinsic and extrinsic types of motivation have been widely studied, and their importance on both developmental and educational practices has led to the development of assessment tools. The Aspiration Index scale (AI; Grouzet et al., 2005), which was developed to measure people`s life aspirations, was translated and validated into Portuguese. A sample of 1,359 adolescents, age ranged from 12 to 18 years-old, participated in the present study. Results showed that a factor structure with the eleven subscales of the AI does not fit the data. However we gathered support for a three-factor structure that organized the items in terms of whether aspirations are intrinsically, extrinsically or self-transcendent oriented. Internal consistency and temporal stability yielded good results. The predictive and criterion validities were demonstrated by significant associations with theoretically supported measures of satisfaction with life and father and mother attachment. The multi-group confirmatory factor analysis showed that this structure was invariant across gender. These results suggest that the AI is a reliable measure to assess different types of life aspirations and can be used in future research with adolescents in Portugal.