We developed and validated a scale to measure job crafting behavior in three separate studies conducted in The Netherlands (total N=1181). Job crafting is defined as the self-initiated changes that employees make in their own job demands and job resources to attain and/or optimize their personal (work) goals. In Study 1 and 2 the Dutch job crafting scale (JCS) was developed and tested for its factor structure, reliability, and convergent validity. The criterion validity of the JCS was examined in Study 3. The results indicated that there are four independent job crafting dimensions, namely increasing social job resources, increasing structural job resources, increasing challenging job demands, and decreasing hindering job demands. These dimensions could be reliably measured with 21 items. The JCS shows convergent validity when correlated with the active constructs proactive personality (+), personal initiative (+), and the inactive construct cynicism (-). In addition, results indicated that self-reports of job crafting correlated positively with colleague-ratings of work engagement, employability, and performance - thus supporting the criterion validity of the JCS. Finally, self-rated job crafting behaviors correlated positively with peer-rated job crafting behaviors. (Contains 4 tables.)