Isla El Tigre volcano is located in the Gulf of Fonseca (Honduras) along the secondary line of the Central America Volcanic Front, where there is a significant break in the strike of the volcanic chain. The studied samples of this poorly investigated volcano are sub-alkaline, mafic lavas with calcalkaline affinity (basalts and basaltic andesites) with the typical characters of a volcanic arc magmatism. On the basis of petrographic and geochemical features, two groups of rocks were distinguished. Lavas from the main volcanic edifice (low-MgO samples) are highly porphyritic. They show a significant LILE and LREE enrichment and Nb depletion and have a strong slab signature as well as incompatible element contents similar to those of the main front of the adjacent volcanoes in El Salvador and Nicaragua (e.g. Ba/La up to 80). In contrast, lavas from the parasitic cones show higher MgO content (> 5 wt.%) and lesser HFSE depletion relative to LILE and LREE, with lower Ba/La, Ba/Nb and Zr/Nb ratios. This suggests that mantle-derived magmas were not produced by the same process throughout the activity of the volcano. The bulk rock geochemistry and Sr–Nd–Pb isotopic data of Isla El Tigre, compared with the other volcanoes of the Gulf of Fonseca and the whole literature data of Central America (main chain and secondary line of Volcanic Front, Behind Volcanic Front and Back-Arc area) suggest this stratovolcano was mainly built by mantle-derived melts driven by fluid-flux melting, while magmas erupted through its parasitic cones have a clear signature of decompression melting, with minor slab contribution. The coexistence of these two different mantle melting generation processes should be linked to the complex geodynamic setting of the Gulf of Fonseca where the volcanic front change direction of ca. 30° and two fundamental tectonic structure of the Chortis block such as the N-S Honduras Depression and the NE-SW Guayape Fault Zone cross each other.