Martin Sekulić (1833–1905) was a mathematics and physics teacher from Karlovac, one of the few high-school professors who were members of the Croatian community of physicists at the time.

[6] He published several works in the Rad journal of the Yugoslav Academy of Sciences and Arts, such as Fluorescencija i calcescencija (1871)[7] and Iztraživanje sunčane duge (1873).

[4] During the period in which Martin Sekulić was the custodian of the science cabinet of his high school, he would inform his students of the very latest discoveries in the world of physics, and by the school year 1880/81 they had amassed a total of 277 machines for demonstration purposes, including a spectroscope modified by Sekulić himself.

The inventor Nikola Tesla noted in his 1919 autobiography My Inventions that when he attended the Kraljevska Velika Realka in Rakovac (Karlovac) between 1870 and 1873, demonstrations of electricity by his "professor of physics" sparked his interest in this "mysterious phenomena" and made him want "to know more of this wonderful force".

[10][11] The details of who was teaching physics at that time and the nature of the demonstrations described have led some to conclude this professor was Martin Sekulić.