This research was designed to construct an instrument, the Self-Empowerment Index (SEI), to measure teachers' internal sense of autonomy and how teachers express their autonomy to others. Thirty-nine paired statement items were included on a first version of the SEI which was pretested using 115 teachers. These 39 items were revised and pilot tested using 258 teachers. Following a series of item analyses, 14 paired statement items were dropped from the SEI. This revised instrument was field tested using 254 teachers. Although further research is needed on the SEI, the index appears to demonstrate sufficient internal consistency and factorial validity to suggest the promise of future use.