The aim of the present study was to develop the epistemological beliefs of eighth grade students through writing-to-learn (WTL) activities. A one-group pretest-posttest quasi-experimental research design was utilized in the study. The sample group consisted of a total of 18 eighth grade students, attending a secondary school in the rural part of Trabzon in Turkey. To improve the epistemological beliefs of students, WTL activities were developed and utilized in the "Matter and its Structure" unit of the science subject. Each WTL activity focused on one dimension of epistemology, such as source of knowledge, organization of knowledge, certainty of knowledge, speed of learning, and learning control. The WTL activities in the study were conducted throughout a total of 24 lessons. Semi-structured interviews were employed to collect data. Beliefs regarding each dimension of epistemology were identified to be at the level of absolutist, multiplist or evaluatist by means of the "Epistemological Belief Levels Rubric". The findings of the study revealed that the WTL activities increased students' levels of the epistemological beliefs. Hence, students' epistemological beliefs can be developed further by dwelling more on the history of science unit within the subject of science by raising students' awareness.