The 'Ndrangheta (/əndræŋˈɡɛtə/, Italian: [(a)nˈdraŋɡeta], Calabrian: [(ɳ)ˈɖɽaɲɟɪta]) is a mafia-type criminal syndicate originating from the Calabria region of Italy. Emerging in the 19th century, it has developed into one of the world's most powerful and pervasive organized crime entities. Characterized by a decentralized, horizontal structure composed of autonomous operating units known as 'ndrine, the organization's foundational structure is based on family and blood relationships. Beginning in the mid-20th century, coinciding with significant emigration from Calabria, 'Ndrangheta clans expanded their operations across Northern and Central Italy, Europe, Australia, and the Americas. The syndicate is reportedly involved in a wide array of illegal activities, including drug trafficking, arms trafficking, money laundering, racketeering, extortion, and loan sharking.

The 'Ndrangheta has historically had a significant ability to influence local, regional and national politics through systemic corruption, intimidation, and collusion, and continues to infiltrate various sectors of the legal economy both within Italy and internationally. Estimates in 2013 suggested the organization's revenue reached €53 billion. A U.S. diplomatic cable from 2010 purportedly estimated that the 'Ndrangheta's illicit activities, encompassing drug trafficking, extortion, and money laundering, accounted for approximately three percent of Italy's GDP. While its origins are contemporary with the Sicilian Cosa Nostra, formal legal designation of the 'Ndrangheta as a Mafia-type organization under Article 416 bis of the Italian penal code occurred in 2010. The Italian Supreme Court of Cassation had reached a similar conclusion in March of the same year.

In folk culture surrounding the 'Ndrangheta in Calabria, references to the Spanish Garduña often appear. Aside from these references, however, there is nothing to substantiate a link between the two organizations. The Calabrian word 'Ndrangheta derives from the Greek word ἀνδραγαθία andragathía meaning "gallantry" or "manly virtue" or ἀνδράγαθος andrágathos, a compound of the words ἀνήρ, anḗr (gen. ἀνδρóς, andrós), i.e. man, and ἀγαθός, agathós, i.e. good, brave, meaning a courageous man. In many areas of Calabria the verb 'ndranghitiari, from the Greek verb andragathízesthai, means "to engage in a defiant and valiant attitude".

The etymological approach is criticised by some historians. John Dickie argues that "the flattering connotations of the word 'Ndrangheta (courage, martial prowess, manliness) indicate that the 'Ndrangheta as a social phenomenon was rooted in the same positive values, and that it only later degenerated into criminality." A historical and sociological approach shows that 'Ndrangheta is actually the most recent of many earlier descriptions of the phenomenon of organised crime in Calabria. Historical evidence suggests, according to Dickie, that the use of 'Ndrangheta as a name for the Calabrian mafia was adopted by Calabrian mafiosi themselves around the time it first appeared in the documentary sources of the Carabinieri in the late 1920s. The word 'Ndrangheta was brought to a wider audience by the Calabrian writer Corrado Alvaro in the Corriere della Sera in September 1955.

Similar to the Sicilian Cosa Nostra, the 'Ndrangheta is structured as a loose confederation of approximately one hundred groups, referred to as cosche or families. Each group asserts authority over a specific territory, typically a town or village, although their control over the monopoly of violence in these areas is not always absolute or fully legitimized. Estimates suggest that there are around 100 of these families, encompassing between 4,000 and 5,000 members within Reggio Calabria. Other estimates indicate a membership of 6,000–7,000 individuals, with a potential worldwide membership reaching approximately 10,000.

The majority of these groups, numbering around 86, are active in the Province of Reggio Calabria. It is also believed that a portion of the reported 70 criminal groups based in the Calabrian provinces of Catanzaro and Cosenza maintain formal affiliations with the 'Ndrangheta. These family groups are primarily concentrated in impoverished towns and villages within Calabria, including Platì, Locri, San Luca, Africo, and Altomonte, as well as in Reggio Calabria, the main city and provincial capital. San Luca is widely regarded as a significant stronghold of the 'Ndrangheta. According to testimony from a former 'ndranghetista, "almost all the male inhabitants belong to the 'Ndrangheta," and the Sanctuary of Polsi has historically served as a meeting place for affiliates. Bosses from regions outside Calabria, including Canada and Australia, are reported to regularly attend meetings at the Sanctuary of Polsi, suggesting that 'ndrine globally perceive themselves as part of a unified collective entity.

The fundamental local organizational unit within the 'Ndrangheta is the locale (local or place), which exercises jurisdiction over a town or a specific area within a larger urban center. A locale may encompass branches known as 'ndrina (plural: 'ndrine), which can be situated in different districts of the same city, in neighbouring towns or villages, or even outside Calabria. Notably, 'ndrine have been established in cities and towns in Northern Italy, particularly in the industrial regions around Turin and Milan.

The presence of the 'Ndrangheta in Northern Italy can be traced back to the early 1960s, driven by a wave of labour migration from Calabria and the implementation of soggiorno obbligato – a policy of mandatory internal exile intended to isolate crime bosses from their home towns and criminal base in Calabria and Sicily. However, lawmakers failed to foresee that this strategy would backfire, effectively facilitating the northward expansion of mafia activity. A notable case is that of Bardonecchia, an alpine town in Piedmont near Turin, where Rocco Lo Presti was relocated in 1963. He was later joined by his cousin, Francesco Mazzaferro. Their criminal involvement in the local construction sector drew the attention of the Parliamentary Antimafia Commission, which conducted its first-ever inspection in Northern Italy in 1973, focusing on Bardonecchia. Lo Presti and Mazzaferro were identified as the dominant figures of the 'Ndrangheta in the Val di Susa area. Ultimately, in 1995, Bardonecchia became the first municipality in Northern Italy to be dissolved for suspected mafia infiltration, resulting in Lo Presti’s arrest.