Sextus Erucius Clarus (died March 146) was a Roman aristocrat. He was Urban prefect and twice consul, the second time for the year AD 146.
Clarus was a friend of the Younger Pliny, who assisted him in obtaining from the Emperor Trajan the latus clavus, allowing him to hold the office of quaestor. A letter from Pliny to Domitius Apollinaris (suffect consul 97) exists where the former asks the latter to help Clarus in his pursuit of the office of plebeian tribune. Clarus is also the addressee of a letter from Pliny.Aulus Gellius writes of Clarus as a contemporary, stating that he was very devoted to the study of ancient literature. An inscription and a passage in the Historia Augusta are our authorities for his second consulship.
The date of his first consulship was estimated by Géza Alföldy as around 117.
Clarus died in 146 while simultaneously holding the posts of consul ordinarius and urban prefect. He was replaced as consul by Quintus Licinius Modestinus and as urban prefect by Quintus Lollium Urbicum
A likely descendent, either son or grandson, is the consul of 170, Gaius Erucius Clarus.