Jens is of Scandinavian origin, derived from the Old Norse personal name "Gennd", which was itself composed of two elements: "geirr" meaning "spear" and "mann" signifying "man". This indicates that Jens was likely a warrior or shield-bearer in its earliest usage. The name has been widely used throughout Scandinavia, with variations such as Jørn in Denmark and Norway, and Jenes in Finland. In some cases, Jens is considered a variant of the name Jan, which itself comes from the Latin "Johannes", meaning "God is gracious". Today, Jens is popular not only in Scandinavian countries but also in Germany and the Netherlands, with notable bearers including Danish footballer Jens Larsen and German musician Jens Kuross.
The name Jens experienced a significant increase in popularity from the early 20th century onwards. In the late 1800s and early 1900s, there were fewer than 10 births with the name Jens per year on average. However, this changed dramatically starting around the 1960s, with a peak of 39 births in 1966. This trend continued throughout much of the rest of the century, with consistently high numbers of births for the name Jens each year, ranging from about 20 to over 30 births per year. However, since around the year 2000, there has been a decline in the popularity of the name Jens, with an average of fewer than 25 births per year in recent years. Overall, there have been a total of 2414 births recorded for the name Jens over this period.