The aim of this study was to evaluate the effect of two novel mixed plant oils on performance, serum immunity, antioxidant capacity and intestinal morphology in weanling piglets compared with soybean oil (SO). A total of 108 piglets [Duroc × (Landrace × Yorkshire), weaned at d 28, weighting 8.80 ± 1.02 kg] were randomly allotted into 1 of 3 dietary treatments with 6 replicate pens per treatment, 3 barrows and 3 gilts per pen. This experiment contained phase 1 (d 0–14) and 2 (d 14–28). Dietary treatments included a control diet (CON; corn-soybean meal basal diet + 5% SO in phase 1 or 4% SO in phase 2), mixed plant oil 1 diet (MPO1; basal diet + 5% MPO1 in phase 1 or 4% MPO1 in phase 2; a mixture of 10% coconut oil, 15% corn oil, 15% linseed oil, 15% peanut oil, 20% palm oil, and 25% SO), and mixed plant oil 2 diet (MPO2; basal diet + 5% MPO2 in phase 1 or 4% MPO2 in phase 2; a mixture of half MPO1 and half extruded corn). Compared with CON, piglets fed MPO (MPO1 or MPO2) had increased (P <  0.05) average daily gain and feed efficiency in phase 1 and overall (d 0–28), and improved (P <  0.05) serum superoxide dismutase (SOD) content on d 14. These piglets also had higher (P <  0.05) serum IgG, SOD, glutathione peroxidase contents, villus height in duodenum and jejunum, and apparent total tract digestibility (ATTD) of ether extract on d 28. Piglets fed MPO2 showed a higher (P <  0.05) IgM content on d 14 and growth hormone content in serum on d 28 compared with CON.