Adverse childhood experiences (ACEs) have been postulated to negatively affect the development of emotional regulation. However, little is known about specific associations between ACEs, depressive symptoms, and alexithymia or its components [i.e. difficulty in identifying feelings (DIF), difficulty in describing feelings to others (DDF) and externally-oriented thinking (EOT)] in patients with major depressive disorder (MDD). The aims of the present cross-sectional study were to (1) compare ACEs (emotional neglect, emotional abuse, physical neglect, physical abuse, sexual abuse) between alexithymic and non-alexithymic patients with MDD; (2) explore whether specific ACEs, depressive symptoms or the interaction between sex and depressive symptoms predicted TAS-20 or its components. The study sample consisted of 186 psychiatric outpatients with MDD (aged 21-61 years, mean 33.87 years, SD 10.88) recruited from the Department of Psychiatry, Kuopio University Hospital between 2016-2019. Alexithymia and its components were assessed using the 20-item Toronto Alexithymia Scale (TAS-20). ACEs were assessed with the Trauma and Distress Scale (TADS). Almost all patients with alexithymia and 80% of non-alexithymic patients reported that they had experienced emotional abuse or neglect, at least sometimes. Approximately 60% of MDD patients reported having experienced physical neglect and 30% described physical abuse. Emotional and physical abuse and neglect predicted DDF score. These findings suggest that among MDD patients, early experiences of emotional and physical abuse and neglect is associated with difficulties in describing feelings in adulthood.