Multilingual families have received limited attention in the field of informal science education, especially in the context of science museums. These families may encounter challenges that do not exist for English-speaking families when engaging in science learning within museums that are primarily designed and developed in English (Ash, 2003; Garcia-Luis et al., 2011). Building on sociocultural theory in relation to family learning and the concepts of family science habitus and capital (Archer et al., 2015; Rogoff, 1990; Vygotsky, 1978), this study focuses on investigating the social interactions among multilingual family members and their interactions with mediation tools available at museum exhibits to support their children's science learning. The research questions guiding this investigation are: (1) how do parents and family members support multilingual children's learning in a science museum through science talk and interactions with and in the exhibits? and (2) How does the family's science habitus play a role in supporting multilingual children's learning through science talk and interactions at the museum? Using a microethnograpic discourse analysis approach, this qualitative study analyzes video recordings of multilingual families' science talk and interactions during their museum visits, along with parent interviews and artifact collection of the families' culture and science habitus. The findings reveal that parents employ various strategies to support their multilingual children's science learning in an English-designed science museum. These strategies include organizing explanatory talk in the home language, facilitating multiple pathways of making connections based on shared knowledge and cultural practices, providing confirmatory and corrective feedback to children's understanding and exploration, and engaging children in basic scientific practices of doing analysis and making interpretations through comparing and contrasting. Moreover, the findings demonstrated how family culture, such as family science capital and habitus, shapes the supports provided by parents with different levels of science capital, including differences in visit agenda, making connection efforts, and exhibit preferences. This study also uncovers the opportunities and challenges faced by multilingual families in utilizing the mediation tools such as signages, museum educators, and translation tools at the museum to support their children's science learning. The findings contribute practical insights for multilingual families seeking to enhance their children's learning experiences in science museums and other informal science learning spaces. Moreover, they provide valuable feedback for science museums to create more inclusive exhibit designs that cater to the needs of their diverse visitors, particularly those from multilingual and multicultural family backgrounds. [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.]