Atharism or Hanbalism (Arabic: الأثرية, romanized: al-ʾAthariyya / al-aṯariyyah [æl ʔæθæˈrɪj.jæ], "of athar")or Arabic: الحنابلة, romanized: al-ḥanābila, is a school of theology in Sunni Islam which developed from circles of the Ahl al-Hadith, a group that rejected rationalistic theology in favor of strict textualism in interpreting the Quran and the hadith.

Adherents of Athari theology believe the zahir (apparent) meaning of the Quran and the hadith are the sole authorities in matters of aqida and Islamic jurisprudence; and that the use of rational disputation is forbidden, even if in verifying the truth. Atharis oppose the use of metaphorical interpretation regarding the anthropomorphic descriptions and attributes of God (ta'wil) and do not attempt to conceptualize the meanings of the Quran by using philosophical principles since they believe that their realities should be consigned to God and Muhammad alone (tafwid). In essence, they assert that the literal meaning of the Quran and the ḥadīth must be accepted without a "how" (i.e. "Bi-la kayfa").

Athari theology emerged among hadith scholars who eventually coalesced into a movement called Ahl al-Ḥadīth under the leadership of Ahmad ibn Hanbal (780–855). In matters of faith, they were pitted against Mu'tazilites and other theological Islamic currents and condemned many points of their doctrine as well as the philosophical methods they used. Atharism is the school of theology used by Hanbalis.

Several terms are used to refer to Athari theology or Atharism. They are used inconsistently, and some of them have been subject to criticism.

The designation Traditionalist Theology is derived from the word "tradition" in its technical meaning as translation of the Arabic term ḥadīth. This term is found in a number of reference works. It has been criticized by Marshall Hodgson (who preferred the term Hadith folk) for its potential for confusion between the technical and common meanings of the word "tradition". Oliver Leaman also cautions against misinterpreting the terms "traditionalists" and "rationalists" as implying that the former favored irrationality or that the latter did not use the ḥadīth. Some authors reject the use of these terms as labels for groups of scholars and prefer to speak of "traditionalist" and "rationalist" tendencies instead. Racha el Omari has applied the designation traditionalist theology in a way that includes both Ashʿarism and Māturīdism.

Athari (from the Arabic word athar, meaning "remnant" or "effect") is another term that has been used for traditionalist theology. The term Traditionism has also been used in the same sense, although Binyamin Abrahamov reserves the term "traditionists" for scholars of the Hadith, distinguishing it from traditionalism as a theological current. The term "Ahl al-Ḥadīth" ("People of the Tradition") is used by some authors in the same sense as Athari, while others restrict it to the early stages of this movement, or use it in a broader sense to denote particular enthusiasm towards the ḥadīth literature.

Since the overwhelming majority of Muslim scholars in the Hanbali school of jurisprudence has adhered to the Athari creed (ʿaqīdah), many sources refer to it as "Hanbali theology", although Western scholars of Islamic studies remark that it would be incorrect to consider Atharism and Hanbalism as synonymous, since there have been Hanbalite scholars who have explicitly rejected and opposed the Athari theology. However, others note that some Shafiʽi scholars also belonged to this theological school, while some Hanbalites in law adopted a more rationalist school in theology. Moreover, extreme forms of traditionalism had not been confined within Hanbalism, and is also part of Maliki, Shafi'i and Hanafi schools. Some authors refer to traditionalist theology as "classical Salafism" or "classic Salafiyyah" (from salaf, meaning "(pious) ancestors"). Henri Lauzière has argued that, while the majority Hanbali creed was sometimes identified as "Salafi" in classical-era sources, using the corresponding nouns in this context is anachronistic.

It is also known as Traditionalist theology or Scripturalist theology. it emerged as a school of theology in the late 8th century CE from the scholarly circles of Ahl al-Hadith, an early Islamic religious movement that rejected the formulation of Islamic doctrine derived from rationalistic Islamic theology (kalām) in favor of strict textualism in interpreting the Quran and the ḥadīth. The name derives from "tradition" in its technical sense as a translation of the Arabic word athar. Its adherents are referred to by several names such as "Ahl al-Athar", "Ahl al-Hadith", etc.