Loneliness and suicidal ideation (SI) are relevant issues. This study aimed to examine the prevalence of death ideation (DI) and SI in the general population across four age groups and to determine the extent to which emotional and social loneliness are associated with SI. Data were collected via an online panel in Slovenia in February 2019 on a representative sample of 991 participants (50.5% men) aged 18 years and over. Participants completed a series of questionnaires on loneliness, suicidality, stress, and well-being. DI, SI, and previous suicide attempts were most common among younger participants. In each age group, several factors appeared as important predictors of SI, with emotional loneliness being a significant factor in all groups. Given the role of emotional loneliness in SI, prevention programs should address loneliness and its correlates across age groups.