Pharmacological activation of peroxisome proliferator-activated receptor-γ (PPARγ) protects the vasculature. Much less is known regarding the cell specific impact of PPARγ when driven by endogenous ligands. Recently, we found that endothelial PPARγ protects against angiotensin II (Ang II)-induced endothelial dysfunction. Here, we explored that concept further examining if effects were sex-dependent along with underlying mechanisms. We studied mice expressing a human dominant negative mutation in PPARγ driven by the endothelial specific vascular cadherin promoter (E-V290M), using non-transgenic (non-Tg) littermates as controls. Acetylcholine (an endothelium-dependent agonist) produced similar relaxation of carotid arteries from non-Tg and E-V290M mice. Incubation of isolated arteries with Ang II (1 nmol/L) overnight had no effect in non-Tg, but reduced responses to acetylcholine by about 50% in male and female E-V290M mice (p<0.05). Endothelial function in E-V290M mice was restored to normal by inhibitors of superoxide (tempol), NADPH oxidase (VAS-2870), Rho kinase (Y-27632), ROCK2 (SLX-2119), NF-κB (NEMO-binding domain peptide), or IL-6 (neutralizing antibody). In addition, we hypothesized that PPARγ may influence the angiotensin 1-7 (Ang 1-7) arm of the renin-angiotensin system. In the basilar artery, dilation to Ang 1-7 was selectively reduced in E-V290M mice by >50% (p<0.05), an effect reversed by Y-27632. Thus, effects of Ang II are augmented by interference with endothelial PPARγ through sex-independent mechanisms, involving oxidant-inflammatory signaling and Rho kinase (ROCK2). The study also provides the first evidence that endothelial PPARγ interacts with Ang 1-7 responses. These critical roles for endothelial PPARγ have implications for pathophysiology and therapeutic approaches for vascular disease.