Shavuot is a two-day Jewish holiday that falls on the Hebrew calendar dates of Sivan 6–7. Here are the coinciding secular dates for the upcoming years:

Shavuot 2018 begins at sundown on Shabbat, May 19, and concludes at nightfall on Monday, May 21. The 10 Commandments are read on May 20. Yizkor is on May 21.

Shavuot in the Coming Years

2019:   June 8-10 / 10 Commandments: June 9 / Yizkor: June 10

2020:   May 28-30 / 10 Commandments: May 29 / Yizkor: May 30

2021:   May 16-18 / 10 Commandments: May 17 / Yizkor: May 18

Note: The Jewish calendar date begins at sundown of the night beforehand. Thus all holiday observances begin at sundown on the secular dates listed, with the following day being the first full day of the holiday. Jewish calendar dates conclude at nightfall.

Also note: In Israel, the holiday is observed for just one day, and Yizkor is recited shortly after the 10 Commandments are read.

Shavuot Info

Prepping for Shavuot? Here are some handy links for you:
What Is Shavuot?
Detailed Shavuot Calendar
Why Eat Dairy on Shavuot?

See Also

When is Rosh Hashanah in 2018, 2019, 2020, and 2021?
When is Yom Kippur in 2018, 2019, 2020, and 2021?
When is Sukkot in 2018, 2019, 2020, and 2021?
When is Shemini Atzeret / Simchat Torah in 2018, 2019, 2020, and 2021?
When is Chanukah in 2018, 2019, 2020, and 2021?
When is Purim in 2018, 2019, 2020, and 2021?
When is Passover in 2018, 2019, 2020, and 2021?
When is the Ninth of Av in 2018, 2019, 2020, and 2021?