Loneliness and social isolation are considered public health problems among older individuals. In addition, both increase the risk of developing cognitive impairment and dementia. The Social Loneliness construct has been proposed to refer to these harmful social interaction-related factors. To define the risk factors of Social Loneliness in individuals with mild cognitive impairment (MCI) and to analyze cognitive, emotional, and functional differences according to the participant's degree of Social Loneliness. Through convenience sampling, 105 participants over 60 diagnosed with MCI were selected. The evaluation consisted of anamnesis and a comprehensive neuropsychological examination. The ESTE-II questionnaire was used to assess Social Loneliness and its three factors: perceived social support, social participation, and use of communication technologies. Personality was measured with the NEO-FFI questionnaire. The predictors of the Social Loneliness factors were as follows; 1) perceived social support (R2 = 0.33): Neuroticism (β= 0.353), depression (β= 0.205), and perceived health (β= 0.133); 2) social participation (R2 = 0.24): Conscientiousness (β= -0.344) and Extraversion (β= -0.263); 3) use of communication technologies (R2 = 0.44): age (β= 0.409), type of cohabitation (β= 0.331), cognitive reserve (β= -0.303), and Conscientiousness (β= -0.247); all p < 0.05. The participants with a higher degree of Social Loneliness showed more depressive symptoms (R2 = 0.133), more memory complaints (R2 = 0.086), worse perceived health (R2 = 0.147), lower attentional performance/processing speed (R2 = 0.094), and more naming difficulties (R2 = 0.132); all p < 0.05. This research represents an advance in detecting individuals with MCI and an increased risk of developing Social Loneliness, which influences the configuration of the clinical profile of MCI.