Energy active composite yarns include at least one textile fiber member of either an elastic or inelastic material, and at least one functional substantially planar filament, which surrounds or covers the textile fiber member. The composite yarns can include an optional stress-bearing member, which also surrounds or covers the textile fiber member. The composite yarns may be multifunctional, meaning the functional substantially planar filament can exhibit combinations of electrical, optical, magnetic, mechanical, chemical, semiconductive, and/or thermal energy properties.