This study examined the formation of nonkin relationships in widowhood, using personal network data from 548 older men and women who lost a partner through death fewer than 10 years earlier. Relationships established after the death of the spouse were cited by 27.6% of the respondents. New relationships with neighbors were cited in particular. New relationships were more often nominated by women than by men. Formation of new relationships was strongly and positively associated with the duration of widowhood, the presence of a new partner, and having put effort into seeking new relationships. The findings suggest that, to gain a proper understanding of why some widowed individuals form new relationships and others do not, knowledge is required about the quality of the social network prior to widowhood.