Marni is a distinctive girls' name in England & Wales, ranking #1107 in 2001 with 18 recorded births. The name reached its all-time peak in 2014 with 48 births ranking #802. Since 1996, the popularity has increased by 200.0%. In 2001, approximately 1 in every 14,888 girls born was named Marni. FALLING Recent data shows the name is currently falling.