  In this article we study the involutions of $\mathrm{O}(V,\mathrm{q})$, an
orthogonal group for a vector space $V$ with quadratic form $\mathrm{q}$ over a
field of characteristic 2. The classification proceeds by discussing conjugacy
classes of involutions arising as a product of transvections, involutions with
respect to a hyperbolic space, and involutions acting nontrivially in the
radical of $V$. We achieve a complete classification of the conjugacy classes
of involutions when the quadratic space $(V,\mathrm{q})$ is non-defective, and
conclude with a discussion of the defective case.
