Microalgal research has made significant progress due to versatile and high‐value industrial applications of microalgal biomass or its derivatives. However, to explore their full potential and to achieve commercial robustness, microalgal biorefinery needs cost‐effective technologies to produce, harvest, and process the microalgal biomass on large scale as higher production and harvesting cost is one of the key hindrances in the commercialization of algae‐based products. Among several other algal biomass harvesting technologies, self‐flocculation seems to be an attractive, low‐cost, and eco‐friendly harvesting technology. This review covers various flocculation‐based methods that have been employed to harvest microalgal biomass with a special emphasis on self‐flocculation in microalgae. Moreover, genetic engineering approaches to induce self‐flocculation in non‐flocculating microalgae along with the factors affecting self‐flocculation and recent research trends have also been discussed. It is concluded that self‐flocculation is the most desired approach for the energy‐ and environment‐efficient harvesting of microalgal biomass. However, its poorly understood genetic basis needs to be deciphered through detailed studies to harness its potential for the algal biorefinery.