Diabetes mellitus prevalence is rising globally, linked to persistent hyperglycemia and endothelial dysfunction. Extracellular vesicles (EVs) play a role in diabetes pathology, involving complex intercellular communication that influences endothelial response. However, the mechanisms by which EVs contribute to endothelial dysfunction under hyperglycemia remain unknown. To investigate the effect of glucose-altered EVs on endothelial cells, we isolated EVs from HBMECs and THP-1 cells under normal- and high-glucose conditions (5.5 and 33 mM). We used NTA, electron microscopy, and LC-MS/MS for EV characterization. HBMECs in RPMI’s default glucose (11 mM) were exposed to 100 ng/mL of each EV condition, and adherent THP-1 CFSE+ cells were quantified. Long-term high glucose activated HBMECs without altering cell viability. Glucose level altered EV secretion, content, and function. For HBMECs, high glucose decreased EV release but shifted their cargo toward metabolism, barrier disruption, and neuronal protein content. For THP-1 cells, high glucose kept the EV release rate and shifted the cargo toward an inflammatory activation profile. Functionally, high-glucose EVs (mainly THP-1-derived) showed a pro-adhesive effect on endothelial cells. Here, we describe the impact of glucose on EV biology and how glucose-altered EVs can influence inflammation and endothelial responses, highlighting the importance of glycemic control in diabetic patients.