This exploratory study investigated how four independent variables, namely post-marital residence, length of time in a single parent family, gender and change in relative age position in the family, affect the closeness of stepsibling relationships. This research focused primarily on families in which stepsiblings lived together in the same household; however, individuals who had stepsiblings living in another location were also included in the study. A sample of 139 people was generated through a purposive method of requesting names of eligible persons from county extension agents in four Western states (Utah, Idaho, Oregon and Arizona), and from ten introductory classes in Family and Human Development and Sociology during the fall and winter quarters of the 1984-1985 school year.Questionnaires were mailed out. Ninety surveys were returned, yielding a response rate of 65 percent . Seventy-five of the instruments were usable (N=75). The analysis consisted of a two way analysis of covariance for the first three variables. A Kruskal-Wallace was used for the dethronement variable given the small numbers in each of the cells. Post-marital residence and gender of the respondents had no discernible effect on the dependent variable in this study. While the variable months in a single parent family did not have a significant effect on the feelings of closeness towards stepsiblings, a positive trend was noted between the two. A strong but non-significant relationship was discovered between the variable of dethronement and the dependent variable. Further analysis was conducted on a separate independent variable, whether or not the respondents were informed about the parental remarriage, and on two dependent variables as follows: feelings towards stepsiblings at the time of remarriage as well as feelings about the actual remarriage, loving relationships between stepsiblings. A significant difference was noted between informed and non-informed respondents and the first dependent variable. A strong but nonsignificant relationship was discovered between the same groups of respondents and the second dependent variable. Implications for therapy were generated from the results of the study. Suggestions for the optimum times to introduce therapy were also given, as well as strategies that would be useful in enhancing stepsibling functioning.