Marni is a distinctive girls' name in England & Wales, ranking #934 in 2012 with 39 recorded births. The name reached its all-time peak in 2014 with 48 births ranking #802. Since 1996, the popularity has increased by 550.0%. In 2012, approximately 1 in every 8,258 girls born was named Marni. FALLING Recent data shows the name is currently falling.