One main obstacle for instructors in inviting students to design knowledge construction is the tension between prioritizing students' ideas and maintaining the scientific validity of the activity. In this study, as a way of supporting students in shaping their own knowledge construction, the establishment of an audience for knowledge was enacted in a knowledge construction activity in a biology course. Applying the multiple case study method, this study aimed to explore whether and how the establishment of an audience for knowledge can support students' shaping of knowledge construction that is both scientifically valid and meaningful to students. The recordings of 26 student discussions and student-produced artifacts were analyzed as the main data sources. Student-created audiences and the epistemic features of knowledge construction processes were identified, and how the establishment of the audience did or did not support students' knowledge construction was inferred. The analysis revealed that the students first explicated their epistemic goals by creating audiences as persons who hold students' uncertainties and then designed processes to resolve these uncertainties. This indicates that the created audiences could explicate the object orientation of student activities, serving as the central axis in the students' subsequent shaping of the process to construct knowledge that is meaningful to themselves. However, the activity had limited value in supporting the students' plans for scientifically valid knowledge construction. The instructional strategies that are needed to support students in maintaining scientifically valid plans in practice are discussed. This study has pedagogical implications for the development of instructional strategies to support students' epistemic agency as they engage in shaping their own knowledge construction.