Blockchain technology has gained significant attention in the recent years due to its promising features. Unfortunately, practical implementations of Blockchain technology consume a lot of energy. Additionally, scaling technology to support a high volume of transactions remains a significant challenge. Improving scalability and efficiency can help the widespread adoption of the technology and make it sustainable. Sharding is an optimization technique that partitions the data stored on a Blockchain network into “shards” or subsets to improve scalability and transaction throughput. This paper reviews Sharding as a Blockchain optimization tool. It discusses how sharding works and some live implementations of the technique in Blockchain networks such as Ethereum, Zilliqa, Aspen, and TON. The objectives, research methodology, and results of the study of Sharding are also presented. The study's findings help Blockchain practitioners improve their Blockchain network’s scalability.