The purpose of this study is to evaluate the efficacy of a dog-assisted group intervention in elderly people with unwanted loneliness; in terms of improving the perception of unwanted loneliness and emotional well-being. To analyze whether differences are obtained in social support and to determine the satisfaction of the participants. Participants will be recruited from a Primary Health Care Center. These objectives will be accomplished through a randomized clinical trial, single blind, two-arm study of AAT for elderly people with unwanted loneliness.

Background: Unwanted loneliness negatively affects the physical and psychological health of older adults, as well as increasing the likelihood of engaging in behaviors harmful to health. This is an increasing reality and is considered a public health problem. Animal-Assisted Therapy (AAT) is a planned, structured, goal-oriented therapeutic intervention directed by health professionals.

Purposes: To evaluate the efficacy of AAT (with therapy dogs) in elderly people with unwanted loneliness. To assess whether there are differences in the scores obtained after the group intervention regarding the perception of unwanted loneliness and emotional well-being. To analyze whether differences are obtained in social support. To determine participants' satisfaction with the group intervention.

Methodology: A two-arm randomized controlled clinical trial (control group (CG) and experimental group (EG)) with a simple blind (evaluator). Participants will be recruited from a Primary Health Care Center: aged 65 or older, diagnosed as "living alone," and experiencing unwanted loneliness. Intervention: The EG will participate in 9 psycho-educational group sessions (once-a week, 90 minutes) with a therapy dog as a facilitator. In the CG, the same sessions will be conducted without the therapy dog. Assessment: UCLA Loneliness Scale, Goldberg Anxiety and Depression Scale, Emotional Well-Being Scale (e-CAP), Duke-UNC-11 Functional Social Support Questionnaire, and Satisfaction Questionnaire.

Inclusion Criteria:

• People who are 65 years of age or older assigned to the Primary Health Care Center.
• With a diagnosis of "living alone" registered in the computerized clinical history.
• Present unwanted loneliness with a score higher than 3 on the Three-Item Loneliness Scale (TIL Scale). The TIL Scale consists of three questions: How often do you feel that you lack company?, How often do you feel excluded?, How often do you feel isolated? The response options consist of a three-level Likert scale: "almost never", "sometimes" and "often"; the results being from 3 to 9 points.
• Delivery of the information sheet and signature of the informed consent.

Exclusion Criteria:

• If in the initial interview they declared having allergy to dogs.
• Significant fear of dogs
• Meets research criteria for a diagnosis of dementia.
• Do not understand or speak Catalan or Spanish

The principal statistician are blind to identifying participant information and group assignment.