Orphan X (2016) is a thriller written by American novelist Gregg Hurwitz.

It is the first in a series of books centred around Evan Smoak. At the age of 12, Evan was enrolled in a secret operation to train orphans as assassins for government agencies. Evan or Orphan X maintains access to the program’s funding and weapons after the secret operation is closed and he becomes a vigilante assassin.

Other books in the series are Buy a Bullet (2016), The Nowhere Man (2017), Hellbent (2018), Out in the Dark (2019), Into The Fire (2020) and The Prodigal Son (2021).