Experiments were conducted between 2014 to 2015cropping seasons in a 3 to 5 years old oil palm fields at Ohosu Sub-Station, Benin City, a rainforest zone of Nigeria. The experimens showed the effects of intercrops (Cassava, Maize and Pepper) on the growth and yield of oil palm. Data were collected on the growth and yields of oil palm in oil palm-intertcropping system. Alley cropping was not detrimental to the growth and yield of oil palm, in particular canopy cover (1.71, 2.52 and 2.86 m) and mean fresh fruit bunch yields (88.8, 89.9. 93.6 kg/plot). The overall biological advantage of the alley intercrops is high in oil palm fields of ages 3 to 5years. The sole and intercrops of cassava, maize and pepper appeared to have optimized use efficiencies of resources (space and nutrients) in the alleys of oil palm of different ages (3 to 5years).