A previous study showed that the Sanders parallelogram illusion has an effect on time-to-collision (TTC) estimation equivalent to that of the spatial illusion. In the current study, we investigated the effects of the Oppel-Kundt illusion (OKI) on TTC estimation. In the OKI, a horizontal interval between two vertical lines that is filled with additional vertical lines appears larger than an adjacent empty interval of the same extent. In each of the 540 trials, a circular object moved from left to right at three different speeds and was occluded at the end of the left interval. The length of the left and the right interval and their filling (filled vs. empty) were varied independently. The participants’ (N = 30) task was to imagine that the object would have continued to move at the same speed and to indicate by pressing a key when it would have reached the outer line of the right interval (prediction-motion paradigm). We found that the mean estimated TTC was significantly longer when the right interval was filled as compared to empty, regardless of the filling of the left interval. This effect was robust across the variations of interval length and object speed. Thus, consistent with the OKI, there is a clear effect of distance perception on TTC estimation. At the same time, our results show that the perceived speed of the visible, moving object remained unaffected by the filling of the left interval.