In this work, 60-GHz wideband, compact vertically polarized end-fire monopole-based Yagi antenna-in-package is proposed for mobile devices. The antenna was arranged like a monopole array, and the size was minimized by utilizing the image effect. Advantages of the proposed antenna structure include reduction of bond-wire loss by inserting a cavity to make the antenna and chip the same height and size reduction due to image effect. For practical use, a proposed antenna is interconnected with CMOS chip via a bond-wire interconnect. The measured results show 4.99dBi peak gain with 3.5dB fluctuation within 60GHz unlicensed band. S-11 bandwidth is 10.6GHz(57.6-67GHz) which corresponds to 16% fractional bandwidth. The total volume of the antenna is 0.74 x 1.14 x 0.15 lambda(3)(0).