Background : There is a recent interest in pupil dilation during the retrieval of autobiographical memory. We pursued this line of research by measuring pupil diameter during the retrieval of self-defining memories, that is, memories that are highly vivid, emotionally intense, and are retrieved to reflect enduring concerns in a person’s life. Methods : We invited 40 participants to retrieve self-defining memories while their pupil activity was recorder with eye-tracking glasses. We analyzed memories regarding specificity (i.e., specific or general) and emotional valence (neutral, positive, negative, or mixed). Results : Analysis demonstrated larger pupil diameter during the retrieval of specific than general self-defining memories. However, no significant differences in pupil diameter were observed across the four emotional categories of self-defining memories. Discussion : The increased pupil size during retrieval of specific self-defining memories can be attributed to the autonoetic experience during retrieval of these memories and/or to the cognitive load as required to construct these memoires. By investigating pupil dilation during the retrieval of self-defining memories, our study provides an original, ecological, and reliable physiological assessment of these memories.