Wedge orthotics are commonly prescribed for patients with hyperpronation and/or low back pain to improve lower limb alignment and to reduce pain. The purpose of this study was to examine the kinetic effects of medial and lateral wedge orthotics during walking and stair negotiation. Twenty-two healthy young adults participated in the study. Each participant wore no wedge (W0) as a baseline and lateral and medial wedge orthotics at 3 degrees and 7 degrees bilaterally (L3, L7, M3, M7) during walking, stair ascent, and stair descent. Ankle, knee, and hip joint moments were calculated using inverse dynamics during the stance phase of walking and the second step of stair ascent and stair descent. L5S1 compression forces were calculated as the sum of L5S1 joint reaction forces and low back muscle forces. Repeated measures ANOVA was used to test for significant differences (p < 0.05). The L7 wedge significantly reduced external knee valgus moments during walking, but increased knee extension moments during stair ascent compared to W0. The M7 wedge significantly reduced ankle inversion moments during stair ascent and descent, but increased ankle eversion moments during walking and external knee varus moments during walking, stair ascent, and stair descent compared to W0. There were no effects of wedge orthotics on L5S1 compressive forces compared to W0. *+ These results support the recommendation that when considering the use of a wedge orthotic, an individual’s foot alignment, the degree of wedge angle, and effects at the knee joint need to be considered.