Oysters are major aquaculture species worldwide. Oyster farming in the US has been growing rapidly during the past two decades partly due to genetic improvements of cultured stocks. The oldest recorded breeding of oysters began in 1960 when Dr. Harold Haskin started breeding eastern oysters for resistance to MSX (multinucleated sphere X disease, caused by protozoan Haplosporidium nelsoni). The development of MSX resistance from selective breeding was rapid, and significant improvement was achieved after five generations of selection. Selection for dermo (caused by protozoan Perkinsus marinus) resistance was effective but relatively slow. Tetraploid oysters were developed in 1993 and enabled commercial production of triploids. Triploid oysters produced from tetraploids offered significant benefits including faster growth, improved meat quality and sterility. The use of triploids has transformed oyster farming in several major producing countries with triploid production accounting for 30 – 70% of farmed oysters. The release of disease-resistant and triploid oysters has contributed significantly to oyster farming in the US. The genome of the Pacific oyster was sequenced in 2012, and rich genome resources have been developed during the past two decades. Genomic data have provided unprecedented insights into the biology and evolution of oysters. With the discovery of genes for production traits, gene-editing provides a new approach for genetic improvement. In oysters, gene-editing has succeeded in the laboratory although no gene-edited animals with altered phenotypes have been produced. Single-nucleotide polymorphism (SNP) arrays have been developed for oysters to enable genomic selection. Preliminary results indicate that genomic selection is effective in improving traits with low heritability such as dermo resistance. As genotyping cost continues to decline and prediction models are optimized, genomic selection may become a common approach to genetic improvement of oysters and contribute to oyster farming.