The construction sector, comprising various participants, plays a crucial role in achieving sustainability but also has a significant environmental impact. The production method and use on non-renewable resources remain two factors that threaten concrete’s sustainability. Admixtures are one of the ingredients used in relatively small quantities to produce concrete. Despite having a relatively minor proportion compared to the other ingredients, they have a significant impact on the quality of concrete. The use of bio-based admixtures has drawn the attention of researchers and industries due to the requirement for sustainable solutions in every element of construction. This paper presents a review of bio-based admixtures, their production procedures, characterization techniques, and their impact on the characteristics of concrete. A succinct description of chemical admixtures, their classification, production methods, and source or base chemicals is provided. More importantly, gaps are highlighted for future research in regard to bio-based admixtures.