We study knots of order 2 in the grope filtration {G h } and the solvable filtration {F h } of the knot concordance group. We show that, for any integer n ≥ 4, there are knots generating a Z ∞ 2 subgroup of G n /G n.5 . Considering the solvable filtration, our knots generate a Z ∞ 2 subgroup of F n /F n.5 (n ≥ 2) distinct from the subgroup generated by the previously known 2-torsion knots of Cochran, Harvey, and Leidy. We also present a result on the 2-torsion part in the Cochran, Harvey, and Leidy's primary decomposition of the solvable filtration.