Marni is a distinctive girls' name in England & Wales, ranking #1065 in 2008 with 28 recorded births. The name reached its all-time peak in 2014 with 48 births ranking #802. Since 1996, the popularity has increased by 366.7%. In 2008, approximately 1 in every 11,277 girls born was named Marni. FALLING Recent data shows the name is currently falling.