The traditional duties of the groom's parents include introducing the bride to the family, hosting an engagement party and planning the rehearsal dinner. Additionally, the groom's parents typically have financial obligations including paying for the flowers of the bridal party and marriage license.
Traditionally, the role of the groom's parents begins as soon as the engagement occurs. If the groom's parents have not yet met the bride, they should introduce themselves and their family. If the parents have met the bride, it is traditional to share a formal congratulations and share a welcoming note to her.
It is also traditional for the groom's parents to host an engagement party for the couple, which serves as a way to introduce the bride and groom's family and friends to each other. Though this is not a requirement, many families do this to establish a rapport between the wedding guests before the wedding.
The groom's father may also help to plan the bachelor party, and the parents pay for and organize the rehearsal dinner. This may be a large or small occasion, but it should not outdo the wedding, nor include more than half of the wedding guests. The groom and his family are also traditionally responsible for certain costs including the marriage license, flowers for the bridal party, the honeymoon and clergy fees.