Many prior studies conducted in museums have focused primarily on exhibits as the main objects for learning. Less progress has been made in studying signage as another meaning-making tool in museums. The present study was designed to understand the role of signage in family learning by answering the following research questions, "How does signage about exhibit content or interaction strategies affect parents' and children's learning and their engagement?" and "What is the role of parent prior knowledge on parents' and children's learning and their engagement?" To address these questions, 45 parent-child dyads with children aged six to seven years were recruited to engage with two exhibits about cars. Fifteen parent-child dyads were assigned to each of three conditions, created by two different types of signage: (1) Content and interaction signage condition, (2) Content signage condition, and (3) No signage condition. In each condition, eight parents with low knowledge in the car domain and seven parents with high knowledge were recruited. Findings showed that parents and children learned and engaged differently across the three signage conditions. Both children and parents in the conditions with signage learned more than children and parents in the no signage condition. By using information from signage, parents in the two signage conditions were able to identify the content of the exhibit more quickly and to shape appropriate educational messages in their conversations with children. Findings also showed that parents with high knowledge were more likely to have the exhibit-focused engagement, which was often oriented to their own interpretation and not always beneficial for children's learning. However, by showing that parent-child dyads in the content and interaction signage condition were most likely to operate and observe the exhibit appropriately and most likely to describe evidence and make appropriate inferences, this study suggested that the interaction signage can be a way to support parents with high knowledge. This study suggested that signage is not only a tool for communicating about the learning opportunities in the exhibit but it can be also a tool for mediating the usage of the exhibit. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]