Marni is a distinctive girls' name in England & Wales, ranking #1104 in 2002 with 19 recorded births. The name reached its all-time peak in 2014 with 48 births ranking #802. Since 1996, the popularity has increased by 216.7%. In 2002, approximately 1 in every 14,072 girls born was named Marni. FALLING Recent data shows the name is currently falling.