Goal fusion refers to the perception that a goal is integrated within one's self-concept. We created a new measure of goal fusion and examined how incremental differences in such fusion results in positive and negative goal-relevant consequences. A pilot study supported the measure's test–retest reliability. Study 1 found that goal fusion uniquely contributed to participants' goal-relevant cognitions and behaviors above and beyond the effects of other related constructs. Study 2 found that higher goal fusion predicted greater goal investments and goal achievement 1 month later. Study 3 found that goal success and failure differentially impacted peoples' self-concept clarity depending on whether they were or were not fused with the goal. Collectively, the findings indicate our goal fusion assessment is a reliable, valid and useful measure.