This review discusses chemical shrinkage (CS) and autogenous shrinkage (AGS) in cementitious systems, their measurement techniques, and factors influencing them. CS occurs during cement hydration, where the volume of hydrated products is smaller than the reactants, leading to shrinkage. AGS is the volume reduction in cement during early hydration, especially at initial setting time. Initially, CS and AGS are similar, but after hardening, they differ. CS is directly related to the degree of hydration and is proportional to the water-to-binder ratio (w/b). A low w/b ratio increases both CS and AGS. Cement composition and supplementary cementitious materials (SCMs) affect both shrinkage parameters. Fly ash (FA) reduces CS and AGS, while slag increases AGS. Bio-fibers also reduce CS and AGS, with up to 54% reduction observed at 2% fiber content. Factors affecting CS and AGS include cement composition, SCMs, w/b ratio, hydration degree, and chemical admixtures. Modeling and prediction of CS and AGS are based on hydration kinetics and stoichiometric equations. The review highlights the importance of controlling these shrinkage parameters to prevent early-age cracking and improve the durability of cement-based materials. Future research should explore the effects of different fibers and bio-fibers on CS and AGS, as well as the long-term performance of cementitious composites.This review discusses chemical shrinkage (CS) and autogenous shrinkage (AGS) in cementitious systems, their measurement techniques, and factors influencing them. CS occurs during cement hydration, where the volume of hydrated products is smaller than the reactants, leading to shrinkage. AGS is the volume reduction in cement during early hydration, especially at initial setting time. Initially, CS and AGS are similar, but after hardening, they differ. CS is directly related to the degree of hydration and is proportional to the water-to-binder ratio (w/b). A low w/b ratio increases both CS and AGS. Cement composition and supplementary cementitious materials (SCMs) affect both shrinkage parameters. Fly ash (FA) reduces CS and AGS, while slag increases AGS. Bio-fibers also reduce CS and AGS, with up to 54% reduction observed at 2% fiber content. Factors affecting CS and AGS include cement composition, SCMs, w/b ratio, hydration degree, and chemical admixtures. Modeling and prediction of CS and AGS are based on hydration kinetics and stoichiometric equations. The review highlights the importance of controlling these shrinkage parameters to prevent early-age cracking and improve the durability of cement-based materials. Future research should explore the effects of different fibers and bio-fibers on CS and AGS, as well as the long-term performance of cementitious composites.