Marni is a distinctive girls' name in England & Wales, ranking #1317 in 1999 with 14 recorded births. The name reached its all-time peak in 2014 with 48 births ranking #802. Since 1996, the popularity has increased by 133.3%. In 1999, approximately 1 in every 20,121 girls born was named Marni. FALLING Recent data shows the name is currently falling.