As an essential alternative for antitumor application, transdermal drug delivery system (TDDS) can directly deliver drugs into the cutaneous lesion site to exert topical or systemic therapeutic effect. Unfortunately, the skin’s stratum corneum barrier has taken a toll on the efficacy of transdermal drug penetration, ultimately diminishing the overall curative effect. To break down the limitation of stratum corneum, microneedles (MNs), which consist of hundreds of micron-scale needles attached to a supporting base, have emerged to remarkably improve the transdermal drug permeability and further bioavailability. Currently, the types of MNs mainly include solid MNs, coated MNs, hollow MNs, dissolving MNs, and hydrogel MNs. The use of MNs for antitumor therapy has the following advantages: (1) Improved drug penetration, especially biomacromolecules and nanoparticles, through the created microchannels after skin puncture. (2) Realizing spatiotemporally controlled drug release by encapsulating multiple chambers. (3) Noninvasive drug delivery with minimal pain. (4) Increased drug accumulation at superficial tumor site with minimal systemic side effects. (5) Strong controllability of the length, size, and shape of the needles for personalized treatment needs.