The purpose of this study was to assess the effectiveness of extension services on capacity building of smallholder livestock farmers in Midvaal Local Municipality, Gauteng Province, South Africa. A simple random sample technique was used to select the participants, so that individual farmers in the study population could have an equal chance of being selected in the study. A structured questionnaire was used to collect data from 148 smallholder livestock farmers. The data gathered from participants was coded and captured in Microsoft Excel. Descriptive statistics such as frequency counts, mean, percentages, standard deviation, ranking order, and inferential statistics such as binary logistic regression were used to analyse the data. Results showed that technical farm visits (M = 3.3, SD = ±1.36) and informal training (M = 3.2, SD = ±1.31) were effective extension methods. Furthermore, they showed that extension services were less effective at enabling farmers to penetrate formal markets (M = 2,0 SD = ±1.06) and access finance (M = 1.9, SD = ±1.01). The binary logistic regression model revealed that gender and farming status were the main variables that significantly (P<0.05) influenced smallholder livestock farmers’ access to extension services. It was concluded that extension services in the study area were playing a major role in the capacity building of smallholder livestock farmers.