With use of self-assessment (SA) of young language learners on the rise, educators of young learners often want to know what SA captures and how best to use it in order to assist their students' learning. This study focuses on understanding how young learners' processes for responding to SA items differ by age and by context of implementation (i.e., whether or not the SA items refer to a specific task, an after-task condition, or are conducted in a decontextualized fashion, a generic condition). The participants were 31 primary school children learning English in Japan. They were divided into 2 age groups (ages 8-9 and 10-12). In both the generic and the after-task conditions, the children were asked to respond to 9 SA items using a 5-point Likert scale. The children's processes for responding to SAs were obtained through guided interviews. Analyses based on Higgins, Strauman, and Klein's (1986) model of self-evaluation processes indicated that, while the children, irrespective of age, drew on a variety of relevant incidents and reference points when responding to SA in the generic condition, they primarily focused on the just-completed tasks and perceived task requirements as reference points in the after-task condition.