This study investigated associations between timing of solid food introduction and childhood obesity and explored maternal characteristics influencing early feeding practices. Cross-sectional data from children 2-9 years (n = 10,808; 50.5% boys) residing in 8 European countries of the IDEFICS study (2007-2008) were included. Late solid food introduction (≥7 months of age) was associated with an increased prevalence of later childhood overweight/obesity among exclusively breastfed children (OR [odds ratio]: 1.38, 95% CI [confidence interval] [1.01, 1.88]). In contrast, early solid food introduction (<4 months of age) was associated with lower prevalence of overweight/obesity among children that ceased exclusive breastfeeding earlier than 4 months (OR: 0.63, 95% CI [0.47, 0.84]). Children that were introduced to solids right after 6 months exclusive breastfeeding and continued to receive breastmilk (≥12 months) were less likely to become overweight/obese (OR: 0.67, 95% CI [0.51, 0.88]) compared to children that discontinued to receive breastmilk. Analyses were adjusted for age, sex, country, birth weight, parental education level, parental body mass index, tobacco use in pregnancy, gestational weight gain, and gestational diabetes. Underweight mothers, overweight mothers, mothers who reported daily smoking during pregnancy, and low-educated mothers were less likely to follow recommendations on breastfeeding and timely solids introduction. Future studies should examine whether guidelines for solid food introduction timing have to distinguish between exclusively breastfed, formula fed, and too early exclusive breastfeeding-ceased infants. There is also need for more prospective studies; recall bias was an important current limitation. In conclusion, health professionals should emphasize benefits of breastfeeding and appropriate solid food introduction, especially to mothers that are less likely to follow recommendations.