<b><i>Background:</i></b> Loneliness is a public health problem that affects many older adults. The subjective nature of loneliness challenges its assessment. Thus, assessing loneliness with valid and reliable instruments is crucial to characterizing the phenomenon and planning adequate interventions. <b><i>Summary:</i></b> This study mapped the instruments validated for the Portuguese older population that assess loneliness. A scoping review was performed. The search for studies was carried out in SciELO, PsycInfo, Scopus, MEDLINE, MedicLatina, Nursing & Allied Health Collection: Comprehensive, CINAHL, and Open Access Scientific Repositories of Portugal. The findings showed three instruments validated for the Portuguese older population: ULS-16, ULS-6, and SELSA-S. <b><i>Key Messages:</i></b> Future testing of those instruments is required to update and accumulate psychometric evidence. In addition, it is important to translate and validate other instruments to the Portuguese older adults population, namely de Jong Gierveld and UCLA-R (most used internationally), as well as the ALONE scale (new and brief).