Norwegian Health authorities recommend solid food to be introduced between child age 4-6 months, depending on both the mother´s and infant's needs. The aim of this paper is to describe timing of complementary feeding in a current sample of Norwegian mother/infant-dyads and explore potential associations between timing of introduction to solid foods and a wide range of maternal and infant characteristics known from previous literature to influence early feeding interactions. The paper is based on data from the Norwegian randomized controlled trial Early Food for Future Health. In 2016, a total of 715 mothers completed a web-based questionnaire at child age 5.5 months. We found that 5% of the infants were introduced to solid food before 4 months of age, while 14% were not introduced to solid food at 5.5 months of age. Introduction of solid food before 4 months of age was associated with the infant not being exclusive breastfed the first month, receiving only formula milk at 3 months, the mother being younger, not married/cohabitant, smoking, less educated and having more economic difficulties. Not being introduced to solid food at 5.5 months was associated with the infant being a girl, being exclusive breastfed the first month, receiving only breastmilk at 3 months, the mother being older, married and having 3 or more children. This study shows that there are still clear socioeconomic differences regarding timing of complementary feeding in Norway. Infants of younger, less educated and smoking mothers are at higher risk of not being fed in compliance with the official infant feeding recommendations. Our findings emphasize the importance of targeting socioeconomically disadvantaged mothers for support on healthy feeding practices focusing on the infant`s needs to prevent early onset of social inequalities in health.