Physiology deals with the life processes of plants, concerning with the functions of cells, tissues, organs or the plant as a whole. Physiology focuses on how organisms, organ system, organs, cells and biomolecules carry out the chemical or physical functions that exist in a living system. Biochemistry is the chemistry of living things concerning with the structure and chemical processes of biological molecules, including proteins, carbohydrates, lipids, and nucleic acids; the mechanisms of enzyme action; the chemical regulation of metabolism; the chemistry of nutrition; the molecular basis of genetics (inheritance); the chemistry of vitamins; energy utilization in the cell; and the chemistry of the immune response. Seed physiology is the study of functions and processes involved in the seed development, in germination and its control, and in the utilization of seed reserve during the early stages of germination and seedling growth. Seed biochemistry is the study of chemical substances and the initial process occurring in seed. The study of the chemistry behind biological processes and the synthesis of biologically active molecules such as carbohydrates, proteins and lipids are examples of biochemistry. Seed development is related with the synthesis and storage of carbohydrates, protein and oil to supply nutrients to the geminating seedling prior to soil emergence. Seed development occurs in several stages: rapid cell division, seed fill and desiccation. Seed development plays a fundamental role in the reproduction and in determining the economic value of different crops. One purpose of studying seed development is to specify the most adequate harvesting movement in terms of maximum accumulation of biological substances and nutrients, and seed vigor, which coincide with physiological maturity and further dehydration or desiccation to reach the harvest point. It is essential to understand the genetic, biochemical and physiological mechanism favoring a higher rate of incorporation of the main reserve components in the seeds such as carbohydrate, protein, lipids, minerals, growth hormones, secondary metabolites and other nutritional factors. A better understanding of phloem discharge may lead to the optimization of reserve compound synthesis in seeds as well as the study of metabolic pathways especially on key enzymatic steps, can potentially lead to a better control of amounts or types of substances stored in the seeds. This document on Seed Physiology and Biochemistry in relation to Seed Development and Maturation is compiled for the benefits of Teachers, Researchers, Scholars and students who are involved in teaching and research in the field of Seed Biology.