While bilingual aphasia has recently gained more interest in aphasiology (Grunden et al., 2020; Kiran & Gray, 2018), hardly any study has examined diglossic aphasia (Widmer Beierlein & Vorwerg, 2020), even though a high number of people worldwide speak a dialect and a standard variety. It is still a matter of debate how the processes of lexical retrieval in bilinguals and diglossics are executed (Costa et al., 1999; Green, 1998; Green & Abutalebi, 2008). Recent studies investigating dialect processing suggest that lexical retrieval mechanisms are comparable to the ones found in bilinguals (Vorwerg et al., 2019). In Switzerland, a high percentage of Swiss people is diglossic. Swiss German dialects (SG) enjoy high prestige and are used for oral communication in most settings, whereas High German (HG) is used for formal communication, reading and writing (Haas, 2004). The current study addresses diglossic word retrieval of nouns and verbs of persons with aphasia (PWA), measuring correctness and naming latency in a picture naming task that includes 33 PWA and 33 healthy controls, all of them with SG as first language. Half of the pictures were named in SG and the other half in HG. The analysis was performed using generalized linear mixed models. PWA are significantly less correct and slower than the control group. Furthermore, the naming latencies show that the control group is faster in SG, while PWA are faster in HG. Within the group of PWA, the naming correctness is significantly higher in HG compared to SG. The study shows that lexical retrieval in healthy diglossic speakers may be similar to language production in bilinguals with faster lexical retrieval in the first language, i.e. the dialect. This effect could not be replicated in the aphasic group, indicating that lexical retrieval and selection mechanisms involved in differentiating between varieties, may be impaired in aphasia and should be taken into account in diagnosis and therapy.