According to Official Guinness Records,
The most flower girls in a wedding is 253, and was achieved at the wedding of Charlene Pearson and Leon Watts (both Australia) in Hita, Japan, on 2 April 2017.Charlene and Leon wanted to attempt this record to bring joy to Hita since the earthquake a year previous to the wedding.
For a complete list of 2017 records, please visit 2017 Guinness Records in Japan.