This thesis examines three cases of insurgency; the 1954 Coup against Guatemalan President Jacobo Árbenz, the insurgent side in the Guatemalan Civil War from 1960-1996 (the thesis will not go beyond 1983), and the insurgency against Fidel Castro’s revolutionary Cuba from 1959 to 1964. All three cases saw heavy involvement from the United States of America, which will be a focus throughout the thesis. Out of the three insurgencies only the one against Árbenz succeeded in toppling a regime, despite consisting of only a small force of 480 soldiers. A combination of unhappiness with domestic reform within the Guatemalan military, and the impression of an impending invasion by the USA created by US propaganda, led to the Guatemalan military toppling their own leader, and giving into US demands for an anti-communist government. The Guatemalan Civil War was long and horribly bloody. The insurgents fought the regime to rid the country of the US backed military dictatorship that succeeded Árbenz. Despite enjoying a time of considerable support and success in the beginning of the 1980s, the insurgency failed to topple the government. The determination of the government to quash the insurgency, as well as its indiscriminate use of violence, and US support, resulted in the insurgency failing. The insurgency against Castro examined in this thesis deals with the period where the USA was most active in the struggle. As a reaction to the revolution, and its continuous move to the left, many Cubans joined different resistance groups against the new regime. From the end of 1960, the USA started to plan for the overthrow of the new government on Cuba. Part of the strategy was to unite the different anti-Castro groups, and to train exile Cubans for armed struggle against Castro. The exile forces were used both for the failed invasion at the Bay of Pigs in 1961, and through a guerrilla struggle before and after the invasion. As with Guatemala, propaganda was used as a tool to weaken the Cuba regime. Despite massive US support for the insurgency, the Cuban government proved resilient, and did not collapse. The thesis concludes by explaining that multiple factors determine whether any particular regime is vulnerable to an insurgency. Due to the complex interaction between different variables, a short, concise, conclusion is impossible to make.