Stock valuation models are techniques used to determine a company's stock intrinsic value, helping investors identify overvalued, undervalued, or fairly valued stocks. Key models include the discounted cash flow (DCF) model, which analyzes future cash flows, the price-to-earnings (P/E) ratio, which compares share price to earnings, and the dividend discount model (DDM), focusing on dividends. Relative valuation models assess valuations against similar companies using various metrics like P/E and price-to-book (P/B) ratios.