Guided by trends of increased prevalence and social acceptance of stepfamilies, the authors argue that stepparents are more likely to include stepchildren in their personal network in recent times. Data are from observations by 2 studies: (a) the Living Arrangements and Social Networks of Older Adults Study and (b) the Longitudinal Aging Study Amsterdam in 1992-2009 of 247 Dutch stepparents age 54-91 years. The results revealed that in 1992, 63% of the stepparents had stepchildren in their personal network, and this percentage increased to 85% in 2009. The network membership of stepchildren was less likely for stepparents from living-apart-together partnerships. Stepmothers less often included stepchildren in their personal network than stepfathers. Both effects may be understood in terms of family commitment. Stepfamily boundaries have become more permeable over time, suggesting that there is an increased potential for support exchange and caregiving within stepfamilies.