Patagonia is a biodiverse area of high conservation priority, and Liolaemus lizards comprise a large component of the endemic fauna. Recent molecular and morphological studies have revealed cryptic species in several Liolaemus groups, including the Liolaemus lineomaculatus section (22 species recognized to date), which is endemic to Patagonia. Despite being a conspicuous component of this area, little is known about the morphological, ecological, and genetic variation of lizards of the L. lineomaculatus section; moreover species limits and past demographic scenarios are still uncertain for many of these species. In this paper, we characterize the morphological, ecological (niche envelope), and genetic variability of the four southernmost species of the L. kingii group (L. lineomaculatus section). Our main goal is to clarify species boundaries (using integrative taxonomy) as well as to infer evolutionary and demographic histories. For this paper we used a total of 241 specimens, 195 of which were used for morphological analyses (10 morphometric, 10 meristic, and 7 qualitative characters) and 226 were sequenced for cytochrome b. We summarized ecological variation by using environmental data from 62 localities of occurrence in a geospatial modeling analysis to estimate current and past species niche envelopes and to test for niche similarity. We identified genetic lineages and evaluated differentiation among them at molecular, morphological, and niche envelope levels. Overall, we found support for the specific status of L. baguali, L. escarchadosi, and L. sarmientoi based on differentiation along each of these three levels. Liolaemus tari is also differentiated from the other species, even though we could not evaluate its niche envelope due to small sample size. We also show the first evidence of possible hybridization among some of these species and recognize a new candidate species.