Use of cold-weather personal protective clothing (PPC) in cold climates is essential but can add metabolic cost to the wearer. This study measured the effect of wearing state-of-the-art PPC and personal protective equipment (PPE), with the possible effect of clothing layers and fit, on physiological responses including metabolic rate (MR) and muscle activation level. 19 male participants (80.2 ± 5.9 kg, 181.5 ± 5.1 cm) wore five different clothing ensembles during level (0°) and inclined (6°) walking. Compared to a base layer ensemble (388.7 ± 42.7 W/737.8 ± 57.9 W), wearing a 3-layer PPC ensemble (421.5 ± 44.7 W/811.7 ± 69.2 W) significantly increased MR, and adding PPE (458.3 ± 59.8 W/864.5 ± 71.2 W) further increased MR during level/inclined walking. Independent of the extra weight, adding a middle layer between base layer and outer clothing significantly increased MR during inclined walking only, and no effect of oversized outer clothing was measured.