Research has shown that recovery processes in general and psychological detachment in particular are important for work engagement. We argue that work engagement additionally benefits from reattachment to work in the morning (i.e., mentally reconnecting to work before actually starting to work) and that the gains derived from psychological detachment and reattachment are stronger in the morning than in the afternoon. We tested our hypotheses in a daily diary study with a sample of 167 employees who completed 2 surveys per day over the period of 2 workweeks. Hierarchical linear modeling showed that work engagement was higher in the morning than in the afternoon. Evening psychological detachment and morning reattachment positively predicted work engagement throughout the day. The association between reattachment and work engagement was stronger in the morning than in the afternoon. This study demonstrates that not only psychological detachment from work during leisure time, but also reattachment to work when coming back to work are crucial for daily engagement at work.