A quinceañera is often crowned with a tiara during the celebration.
The crowning is one of several symbolic presentation rituals associated with the event. A parent, godparent, or another important person may place the tiara on the celebrant, emphasizing her special status on the fifteenth birthday. The precise person and timing differ among families and regions.
A tiara is not a universal requirement. Some celebrations use a crown, a family keepsake, or no headpiece at all. Likewise, the ceremony may be religious, secular, or a combination of both. The symbolism is therefore more consistent than the physical design of the item.
The tiara also connects the formal clothing and photography of the event with the idea of a public presentation. It should not be confused with a graduation cap, which belongs to an academic ceremony rather than the quinceañera tradition.