90 emerging adults were asked to report on one of their sibling relationships. This cross-sectional design, correlational study examined the qualitative features of these relationships and explored how they related to coping strategies, perceived stress and life satisfaction of the respondents. Through an online survey and using in-class questionnaires, participants completed the Adult Sibling Relationship Questionnaire, the Brief COPE, the Perceived Stress Scale and the Satisfaction with Life Scale. Results showed that sibling warmth and conflict were related to use of different coping strategies. Conflict levels correlated positively with stress. Warmth was positively related, and conflict and rivalry were negatively related to life satisfaction. Poor sibling relationship quality can have a negative impact on well-being and is associated with avoidant coping strategies which are not considered effective in the long-term management of stress. Findings highlight the important role siblings have in emerging adulthood.