Context: Angiopoietin-like protein 4 (ANGPTL4) decreases plasma triacylglycerol (TAG) clearance by inhibiting lipoprotein lipase (LPL) and may contribute to impairments in lipid metabolism under compromised metabolic conditions. Objectives: To investigate the effects of a high-saturated fatty acid (SFA) mixed meal on plasma ANGPTL4 concentrations in relation to in vivo muscle LPL activity, to study the effects of dietary fat quality, and to examine skeletal muscle ANGPTL4 release. Design, Participants, Setting, and Interventions: We used a dual stable-isotope tracer technique in combination with measurements of arteriovenous concentration differences across forearm muscle to investigate muscle ANGPTL4 secretion and fatty acid handling under fasting conditions and after a high-SFA mixed meal in 73 overweight and obese humans at the Metabolic Research Unit of Maastricht University. The effect of dietary fat quality manipulation on plasma ANGPTL4 was investigated in 10 obese insulin-resistant participants. Results: The high-SFA meal decreased circulating ANGPTL4 concentrations (fasting, 5.2 ng/mL; vs 4 hours postprandial, 4.0 ng/mL; P <.001). Furthermore, skeletal muscle ANGPTL4 secretion into the circulation was observed (AUC(0-4) (h), P = .048). However, no association was observed between plasma ANGPTL4 and skeletal muscle very low-density lipoprotein or dietary (chylomicron) TAG extraction (AUC(0-4) (h), P = .372 and P = .139, respectively). In contrast to a high-SFA or high-monounsaturated fat meal, plasma ANGPTL4 remained unchanged after a high-polyunsaturated fat meal. Conclusions: ANGPTL4 is secreted by human forearm muscle in postprandial conditions after a high-SFA meal. Plasma ANGPTL4 concentrations were not associated with in vivo skeletal muscle LPL activity after a high-SFA meal. Dietary fat quality affects plasma ANGPTL4, but it remains to be elucidated whether this influences short-term skeletal muscle lipid handling.