Lucius Julius Marinus Caecilius Simplex

Lucius Julius Marinus Caecilius Simplex was a Roman senator who held several posts in the emperor's service. Simplex was then appointed suffect consul in late 101, with Lucius Arruntius Stella as his colleague. His career is primarily known through inscriptions.

His polyonymous name indicates that Simplex was either adopted, or incorporated his mother's name; the consensus is that he incorporated his mother's name into his. His father has been identified as Lucius Julius Marinus, attested as governor of Lower Moesia in January 97, and whose tenure as suffect consul has been dated around AD 93. His mother is considered a daughter of Gnaeus Caecilius Simplex, one of the suffect consuls of 69.