Bitumen emulsion is an important building material, especially in highway pavement construction. It is a mixture of bitumen (asphalt), water and emulsifying agent, dispersed in tiny particles in an aqueous medium. It is an important material widely used in the pavement construction ever since the first introduction in the year 1900’s. This paper aims to provide an overview and an understanding among the practitioners on the bitumen emulsion from the manufacturing process, naming and categorizing to its potential application. Bitumen emulsion can be manufactured in a batch plant or in-line plant. Being water based, it is capable to be applied under ambient temperature besides being more environmental friendly. Categorizing the bitumen emulsion is simple but the naming may differs slightly according to local specification. Continuous research also has end up in the modification of conventional bitumen emulsion using polymers to produce polymer modified bitumen (PMB) emulsion which decreases thermal susceptibility and permanent deformation (rutting). It has resulted in even wider application of bitumen emulsion as in microsurfacing, slurry seal and cape seal.