Hearing loss is the third most prevalent health condition in older age. In recent years, research has consistently reported an association between hearing loss and mental health outcomes, including poorer cognitive performances. Whether treating hearing loss in elders improves cognition has been directly or indirectly addressed by several studies. This review aims at providing a synthesis of those results. Regarding the literature on hearing aids' use and cognition, although the lack of interventional studies has to be underlined, observational data suggest that hearing aids positively impact long-term cognition, even though more research is necessary to ascertain this statement and provide information on the length or frequency of use required in order to observe benefits. Regarding cochlear implants in elders experiencing more severe auditory deprivation, the literature is scarcer. The available studies have many limitations and do not allow the drawing of clear conclusions. Taken together, the results are encouraging. Nevertheless, because hearing loss is suspected to account for 9% of dementia cases, and also because hearing loss is one of the few potentially modifiable factors from a dementia prevention perspective, the need to stimulate research to have clearer knowledge of the benefits of treating hearing loss on cognitive outcomes is urgent.