Strasserism (German: Strasserismus or German: Straßerismus) refers to a dissident, far-right ideology based on Nazism, named after brothers Gregor and Otto Strasser, who were associated with the early Nazi movement. It shares Nazism's core rhetoric of revolutionary nationalism, anti-capitalism, antisemitism, and anti-communism, as well as its populist tactics. Fundamentally, it fits into a broader "Third Positionist" pattern of strategically appropriating socialist-sounding rhetoric to advance an ultranationalist agenda, a tactic it shares with foundational historical fascist movements, including those of Hitler and Mussolini.

The ideology is primarily the creation of Otto Strasser, who promoted what he claimed was a more "authentic" and revolutionary "German Socialism" in opposition to Hitler. His vision called for a radical restructuring of society based on a romantic, anti-modernist rejection of urban industrialism, aiming for a "de-proletarianized" agrarian society structured around medieval-style fiefs (Erblehen) and trade guilds.

In contrast, his brother Gregor Strasser remained within the Nazi leadership until his resignation in 1932. Characterized by historians as a pragmatic party organizer rather than a committed ideologue. Gregor's strategy was not revolutionary schism but internal persuasion; he sought to gain power by convincing Hitler to accept pragmatic coalitions and compromises with the existing state. He never joined Otto's dissident movement and was ultimately murdered during the 1934 Night of the Long Knives.

Despite its "anti-capitalist" and "revolutionary" self-portrayal, the historical credibility and originality of Strasserism are subjects of significant scholarly debate. Otto Strasser's accounts of his conflict with Hitler are considered unreliable by historians, the originality of the foundational programs is also highly questionable. Most notably, the 1932 Sofortprogramm, a key economic platform promoted by Gregor, was largely plagiarized from Robert Friedländer-Prechtl, an economist of partial Jewish descent who belonged to a circle of bourgeois reformers advocating for state intervention to save the system—a program whose core policies were ironically later implemented by the Hitler regime after its nominal author, Gregor, had been murdered. Politically, Otto's 1930 split from the Nazi party is noted as having had minimal impact, despite at times receiving material support from figures as diverse as British intelligence and, according to his own claims, certain German industrialists.

In the post-war era, the "Strasserist" label itself was repurposed as a strategic guise for various far-right groups. In an era where overt Nazism was legally proscribed, both Strasser's own followers and figures with direct continuities to Hitlerite Nazism co-opted the "Strasserist" framework. According to historian Christoph Hendrik Müller, this allowed them to use its nominally "anti-capitalist" and anti-liberal rhetoric as a publicly acceptable vehicle for coded antisemitism, while tactically distancing themselves from the Hitler regime.

Like mainstream Nazism, Strasserism posited the nation and its "nature", rather than class, as the central organizing principle of society. However, Strasserism's primary distinction from mainstream Nazism lay in its detailed and unique ideological framework for a radical, total restructuring of society. Otto Strasser advocated for what he claimed was a more authentically socialist alternative to what he condemned as Hitler's state-managed capitalism, which he labeled "German Socialism." He contrasted his vision with what he considered Hitler's deviation from the movement's original path, particularly the party's dealings with capitalist interests, as well as Hitler's specific strategies for seizing power.

To further frame this distinction in left-right terms, Strasser consistently portrayed his own faction as the genuine "left-wing" of the Nazi movement. In his 1943 memoir Flight from Terror, he claimed that the Nazi Party was only perceived as the "Rightest" party due to Hitler's "pro-monarchist statements and industrial support," while asserting his own Prussian membership was "far more left than right". In the same passage, he presented General Erich Ludendorff—a key figure in the Beer Hall Putsch, icon of the militarist right—as his faction's own candidate, meant as an alternative to the mainstream conservative candidate, and depicts him as a heroic figure. Although in his book Germany Tomorrow, published three years prior to this memoir, Strasser portrayed the rejection of Prussian militarism as one of his key political objectives, going so far as to condemn Prussia itself as an "appendage to Russia" in order to justify its partition.

Strasser frequently equated Hitler's regime with both Mussolini's Fascism and Stalin's Bolshevism, dismissing all three as forms of totalitarian "State Capitalism" defined by oppressive bureaucracy. He explicitly repudiated "State Socialism" as well, which he considered merely a euphemism for the same system. In contrast to what he condemned as "bureaucracy," he presented his own model as the realization of a true "people's State" (Volksstaat). By reserving the specific label of "fascism" for his rivals Hitler and Mussolini, and consistently presenting his own ideology as the only genuine "National Socialism," he sought to carve out a unique ideological space for his movement.