With supply chains spanning the globe, and with increasing time-sensitivity for various products in many markets, timely deliveries are becoming a strategy, as important as productivity, quality, and even innovation (see, e.g., Gunasekaran, Patel, and McGaughey (2004), Christopher (2005), and Nagurney (2006)). A product is considered to be time-sensitive, if there is a strict time requirement regarding that product, either as a characteristic of the product itself or on the demand side. In particular, a time-sensitive product must have at least one of the following two properties: 1. the product loses its value rapidly, due to either obsolescence or perishability, which can lead to extra waste and cost, if unused; 2. the demand for it is sensitive to the elapsed time for the order fulfillment; the failure to satisfy the demand on-time may result in the loss of potential market share, or, even worse, additional injuries or death as in times of crises. This dissertation formulates, analyzes, and solves a spectrum of supply chain network problems for time-sensitive products, ranging from fast fashion to food to pharmaceuticals. Specifically, I first develop a model that captures the trade-offs between the operational costs and time issues in the apparel industry. I then construct a sustainable fashion supply chain network model under oligopolistic competition and brand differentiation. I, subsequently, capture the deterioration of fresh produce along the entire supply chain through arc multipliers with time decay. Finally, I consider the supply chain network design problem for critical needs products, as in times of crises and humanitarian relief operations. I also develop a supply chain network design/redesign model with multiple products, with particular relevance to healthcare. This dissertation consists of advances in the modeling, analysis, and design of supply chain networks for time-sensitive products, all unified through the methodology of variational inequality theory (see Nagurney (1999)), coupled with network theory and multicriteria decision-making. The framework captures the underlying behavior associated with the operation and management of the associated supply chains, whether that of central optimization or competition, allows for the graphical depiction of the supply chain network structures, and efficient and effective solution.