The five good emperors were a series of five emperors of the Roman Empire who ruled in the 2nd century A.D. The five emperors were known for their moderation and their reign corresponds to the period known as the Pax Romana. Lasting from AD 96 to 180, these emperors were Nerva, Trajan, Hadrian, Antoninus Pius, and Marcus Aurelius. Among the Roman emperors, the period of the five good emperors was particularly notable for the peaceful method of succession. Each emperor chose his successor by adopting an heir, thus preventing the political turmoil associated with the succession either before and after this period. Because none of the emperors were related, the five good emperors are not considered a dynasty.

This opinion of well-being is best expressed by the historian Edward Gibbon:

If a man were called to fix the period in the history of the world during which the condition of the human race was most happy and prosperous, he would, without hesitation, name that which elapsed from the death of Domitian to the accession of Commodus. The vast extent of the Roman Empire was governed by absolute power, under the guidance of virtue and wisdom. The armies were restrained by the firm but gentle hand of four successive emperors, whose characters and authority commanded respect. The forms of the civil administration were carefully preserved by Nerva, Trajan, Hadrian, and the Antonines, who delighted in the image of liberty, and were pleased with considering themselves as the accountable ministers of the laws. Such princes deserved the honour of restoring the republic had the Romans of their days been capable of enjoying a rational freedom.

However, more recent historians, while agreeing with many of the details of this analysis, would not entirely agree with Gibbon's praise of this period. There were more people under the rule of these emperors than the few affluent individuals whose lives are mentioned or recorded in the historical record, the vast majority of whom were subsistence farmers or their dependants, who lived their lives always at the whim of rapacious landlords, avaracious government officials, or unrestrained bandits as much before the reign of these "Good Emperors" as during -- and after. The extent to which these people suffered or were happy continues to be subject of historical debate.