Guatemala's long-standing territorial claim against Belize delayed normalization of relations between the two countries until September 1991. Guatemala claimed it inherited Spanish sovereignty over the British settlement following Guatemala's independence from Spain, and Spanish sovereignty over the territory had been recognized by Britain in the Convention of London signed in 1786. Britain rejected Guatemala's claim, however, because Guatemala had never effectively occupied present-day Belize's territory. Britain's own occupation of the area and its 1859 treaty with Guatemala, which set boundaries for what soon became British Honduras, paved the way for a British assertion of full sovereignty over the colony in 1862.

The 1859 treaty, however, included a provision for Britain to assist in the construction of a road from Guatemala City to the Caribbean coast. Guatemala has consistently claimed that this provision was a condition for ceding the territory to Britain. Guatemala claims the treaty was never fulfilled because the road was never built, so the country nullified the cession of territory. Britain, which had offered financial contributions toward the road construction at various times, rejected Guatemala's interpretation of the treaty. Britain believed that Guatemala was not in a position to cede the territory because it never possessed sovereignty over British Honduras. Between 1945 and 1985, Guatemalan constitutions claimed British Honduras as part of its national territory. A provision in the charter of the Organization of American States (OAS) reflected Latin American support for Guatemala's claim. The provision effectively barred membership to an independent Belize without a resolution of Guatemala's claim. Latin American support was also reflected in a provision in the treaty that established the Central American Common Market calling for the integration of Belize into Guatemala.

Subsequent negotiations, including United States mediation in 1965, produced recommendations viewed as highly favorable to Guatemala but failed to produce a settlement acceptable to all parties. At various points in the 1960s and 1970s, Guatemala threatened to invade if British Honduras became independent without resolution of its claim. The British military presence in British Honduras forestalled any invasion. To win Guatemalan acceptance of Belizean independence, however, Britain opposed in the 1970s any postindependence security guarantees to Belize and apparently favored ceding a small strip of territory between the Moho and Sarstoon rivers in southern Belize. Territorial concessions were highly unpopular among Belizeans.

With full independence blocked by inability to reach agreement with Guatemala and by the unwillingness of Britain to make security guarantees, Belize launched a foreign relations campaign in the mid-1970s to win the support of the world community. Building on support within the Nonaligned Movement, Belize gradually won broad support in the General Assembly of the United Nations (UN). The Latin American community began to shift its support from Guatemala 10ee to Belize. Cuba consistently supportly Belize's right to selfdetermination , Panama and Mexico voiced support for Belize in 1976 and 1977, respectively, and they were joined by Nicaragua in 1979. The United States, however, abstained from voting on Belizean independence resolutions introduced annually in the General Assembly. Then in 1980, with Guatemala refusing to vote and seven countries abstaining, 139 countries, including the United States, voted for a UN resolution calling for Belizean independence with territorial integrity by the end of 1981. The OAS subsequently endorsed this resolution.

Given the international support for this timetable, Belize, Britain, and Guatemala again sought a negotiated settlement. On March 11, 1981, the three parties signed an agreement known as the Heads of Agreements. The agreement laid out sixteen subjects, or heads, that were to be agreed to in a formal treaty at a later date. Popular reaction to the Heads of Agreement was overwhelmingly negative in Belize, and rioting ensued to protest what were perceived to be "unwarranted and dangerous" concessions to Guatemala. Furthermore, Guatemala rejected details of the settlement process and withdrew from the negotiations. The British decision to make security guarantees to Belize, however, enabled Belizean independence to go forward.

Subsequent negotiations with Guatemala in the early 1980s were unsuccessful. In 1985, however, Guatemala promulgated a new constitution that did not include the earlier claims to Belize. Rather, the new constitution treats the Belize question in its transitory provisions, giving the executive the power to take measures to resolve the territorial dispute in accordance with the national interests, but requiring any definitive agreement to be submitted to a popular referendum. The article in the provisions also calls for the government of Guatemala to "promote social, economic, and cultural relations with the population of Belize." After on-and-off negotiations in the late 1980s, including the appointment of a permanent joint commission in 1988, substantial progress was made in 1990, following a meeting between Prime Minister George Price and President Vinicio Cerezo Guatemala. In October 1990, Belize's minister of foreign affairs, Said Musa, stated that the preliminary talks on the drafting of a treaty (that would be submitted to popular referenda in both countries) had moved beyond territorial claims to questions of economic cooperation.

On August 14, 1991, Guatemalan President Jorge Serrano Elías acknowledged that Belize was recognized internationally, recognized the right of the Belizean people to self-determination, and stated his willingness to settle the dispute, all without dropping Guatemala's territorial claim. On August 16, 1991, Said Musa introduced a bill to extend Belize's maritime territorial limits to twelve nautical miles, in accord with current international law. The bill stipulated, however, that an exception would be made in the south allowing Guatemala access to international waters from its Caribbean coast in the same way that Mexico has access from its port of Chetumal. Minister Musa has said that the concession to Guatemala was made as a sign of good faith to promote settlement of Guatemala's territorial claim. In a further sign of improving affairs, Guatemala and Belize established full diplomatic relations in September 1991.

Data as of January 1992