The name has been around for around 200 years and first became popular in the latter part of the 20th century on the back of the popular television series Bewitched. The show was first screened in 1964 with the main star named Samantha.
Since the 60s it has regularly featured amongst the most popular girl's names in the United States and was a mainstay in the top 10 between 1988 and 2006. The name is now fairly popular throughout the English speaking world with many Samanthas appearing on film, television and in the music industry.
Samantha is often shortened to Sam or Sammy with those abbreviations especially popular in the UK. During the 80s Sam Fox was a very popular English glamour model appearing regularly in newspaper and television chat shows as her career developed.
Between 2007 and 2009, American Network ABC produced a television series called Samantha Who, which was about the vice-president of a real estate company that developed retrograde amnesia following a hit and run accident. Samantha, played by actress Christina Applegate, realises that she had become selfish and unlikeable before the accident and makes amends, especially to her parents.
The name Samantha is much more popular than the boy's equivalent name, Samuel, which dates back to biblical times. Perhaps the popularity of Samantha has had some impact on the decline in popularity of Samuel since the abbreviations Sam and Sammy have a strong female association.
As a girl's name there is no sign of Samantha falling out of favour, whilst it may have dropped from its peak at the turn of the century, Samantha has remained a popular name for around 50 years.