In vitro human skin models have evolved from reconstructed epidermal and full-thickness tissues to more diverse platforms that combine multicellular organization with increasingly precise control over tissue architecture and the culture microenvironment. This growing diversity increases the need for clear classification and fit-for-purpose evaluation. This review organizes current in vitro human skin models according to biological architecture, including reconstructed epidermal, dermal, full-thickness, and multilayered equivalents, spheroids, and skin organoids, and separately considers vascular, immune, neural, pigmentary, and microbial components as functional extensions. We further examine engineering strategies to construct, mature, and control these systems, including conventional tissue engineering, biomaterial design, three-dimensional bioprinting, microfluidic platforms, and stem-cell-based differentiation. For wound healing, toxicological testing, and disease modeling, we examine which functions each model reproduces, how reproducibly it performs, and how far it has progressed toward experimental, clinical, or regulatory validation. Future development should prioritize models that reproduce the biological functions required for a defined application while remaining experimentally controllable, reproducible, and appropriately validated for that context of use.