A building form system including a plurality of forms for assembling into a wall template that is filled with concrete to create a building wall. The system includes a corner form assembly comprising an inner corner form and an outer corner form for disposition on a corner footing. The outer corner form includes walls angled from a bend. A pair of connectors are disposed on opposite ends from the bend. The inner corner form includes corresponding connectors for attachment to the outer corner form around a preset vertical rebar in the corner footing. The system further includes a base form extending between a first pair of connectors that include a peripheral wall disposed directly therebetween and the second pair of connectors for mating engagement with the first that include an inset wall spaced inwardly therefrom. Spacing between the peripheral and inset wall of adjacent base forms accommodating vertical rebar.