The so-called Lopnor dialect is arguably the most aberrant of the main dialects of Modern Uyghur. Malov was struck by its peculiar developments, leading him to devote a separate book to Lopnor, rather than including it in his book on Uyghur dialects. At first sight, Lopnor distinguishes itself from its relatives mainly in the field of phonetics. Fourfold vowel harmony in the low vowels and numerous consonant assimilations give it a distinctly non-Uyghur appearance. Although the non-Uyghur features of Lopnor have been attributed to “Old Kirghiz” (a variety of Old Turkic) ancestry, several of them are in fact comparable to modern Kirghiz. This article investigates whether it is warranted to assume the presence of a Kirghiz-like layer or component in Lopnor and discusses similarities and differences between Lopnor, Standard Uyghur and Kirghiz, as well as the characteristics which cannot readily be connected to other Turkic languages. The focus is on systematic and incidental phonetic developments. The paper concludes with a brief selection of morphological and lexical features.