The effect of plastic deformation induced by wire drawing on thermal properties in twinning-induced plasticity (TWIP) steel has been investigated. The investigation on the relationship between thermal conductivity (k) and the microstructure in the drawn TWIP steel wire was systematically performed to accurately understand the behavior of the k of a metal during wire drawing. The yield and tensile strengths linearly increased with drawing strain owing to the deformation twins and dislocations that were generated during wire drawing. However, the total elongation sharply decreased with drawing strain. The linear thermal expansion coefficient of the TWIP steel exhibited a similar value regardless of drawing strain. The density decreased linearly with temperature, and it was independent of the drawing strain. k increased initially and then decreased after reaching its maximum value with increasing drawing strains. At a nominal drawing strain of 0.26, k increased compared with the state of hot rolling because the increase in k due to grain elongation was greater than the decrease in k due to dislocations generated during wire drawing. However, as the amount of drawing step increased further, the influence of dislocations on k increased more than that of grain elongation, causing k to decrease.