This study examined the role of temperament, prereading skills, and age at school entry in the development of Finnish children's task avoidance. Teachers rated the task-avoidant behavior of 198 participants in kindergarten and twice in Grades 2 and 3. Parents rated the children's temperament at age 3 and children's prereading skills were measured at age 5. The results showed that, on average, the level of children's task avoidance remained the same from kindergarten to Grade 2 fall, but decreased from Grade 2 fall to Grade 3 spring. A low task avoidance level was predicted by good prereading skills, high effortful control, and high negative affectivity. Low surgency predicted a decrease in task avoidance from kindergarten to Grade 2 fall, whereas high negative affectivity predicted a decrease from Grade 2 fall to Grade 3 spring. Finally, task avoidance of the oldest children in the classrooms decreased more from kindergarten to Grade 2 fall, whereas younger children's task avoidance decreased particularly from Grade 2 fall onward.