Joslyn is a distinctive girls' name in United States, ranking #641 in 2010 with 461 recorded births. The name reached its all-time peak in 2010 with 461 births ranking #641. Since 1996, the popularity has increased by 137.6%. In 2010, approximately 1 in every 3,855 girls born was named Joslyn. FALLING Recent data shows the name is currently falling.