<p>Based on the Work-Home Resources model, the present study examines how flexibility i-deals (idiosyncratic deals) are associated with employees’ caregiver-recipient relationship quality and consequently their work performance. Further, this study examined the crossover effect of flexibility i-deals on an important family outcome (i.e., spouse-rated relationship conflict) through caregiver-recipient relationship quality and positive crossover transmission. Finally, employees’ eldercare burden was tested as an important boundary condition of the relationship between flexibility i-deals and caregiver-recipient relationship quality. Using a three-wave time-lagged design, Study 1 (<i>N</i> = 149 American employees with informal eldercare responsibilities) found that flexibility i-deals were positively related with focal employees’ work performance (i.e., higher in-role task performance and lower counterproductive work behaviors) through caregiver-recipient relationship quality. Study 2 further tested the overall research model in a matched sample of 313 Chinese employees with eldercare responsibilities and their spouses. We found that flexibility i-deals were indirectly related with employees’ work performance through caregiver-recipient relationship quality. Further, we found that flexibility i-deals were indirectly related with the spouse-rated relationship conflict with the focal employee through caregiver-recipient relationship quality and positive crossover transmission. However, eldercare burden did not significantly moderate the relationship between flexibility i-deals and caregiver-recipient relationship quality. Theoretical and practical implications and suggestions for future research are discussed.</p>