Julius Lothar Meyer was a German chemist. He was one of the pioneers in developing the earliest versions of the periodic table of the chemical elements. The Russian chemist Dmitri Mendeleev and he had both worked with Robert Bunsen. Meyer never used his first given name and was known throughout his life simply as Lothar Meyer.

The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order of their atomic numbers an approximate recurrence of their properties is evident. The table is divided into four roughly rectangular areas called blocks. Elements in the same group tend to show similar chemical characteristics.