Gospel Day, celebrated in Kosrae, Micronesia, is a significant holiday that marks the arrival of Christianity on the island. The holiday is also known locally as Sinlaku, which means Sunday in the Kosraean language. This day is incredibly special since it signifies a landmark shift in the islanders' culture and traditions with the introduction of Christianity into their lives.

On this day, the people of Kosrae engage in various social and religious activities. These include church services where the Gospel is read out in local languages, communal feasts, and singing Christian hymns. It is a day marked by solidarity, spiritual reflection, and deep respect for Christian traditions. People also use this day to remember and honor missionary Robert W. Logan who played a pivotal role in spreading Christianity in Kosrae.

The state of Kosrae, represented by 'KO', is one of the primary regions in Micronesia that observes Gospel Day. This day is an official public holiday, resulting in government offices, schools, and various businesses shutting down in observance. Consequentially, Gospel Day in Kosrae proves itself integral to the island's cultural heritage, religious identity, and belief system.