Find our SPSS Dataset belonging to the yet to be published work “Loneliness is associated with retrospective self-reports of adverse childhood experiences – A replication study in Ethiopia”. This cross-sectional study is investigating the interplay between adverse childhood experiences, loneliness, social network size, and mental health problems in Ethiopia in a clinical and non-clinical group. The study sample consists of 125 psychiatric outpatients at Jimma University Medical Center, South-West of Ethiopia, suffering from major depressive disorder, bipolar disorder, or psychotic disorders, and 131 non-clinical study participants. Led by an interviewer, participants completed the UCLA Loneliness Scale, the Childhood Trauma Questionnaire, the Social Network Index, and the WHO-5 Well-Being Index. Definitions of the variable values and additional information can be found in the attached Codebook.