A meta-analysis of feed additives that could influence finishing pig’s growth and carcass performance and feed efficiency was conducted and considered the following additives: acidifiers, betaine, Cr, conjugated linoleic acid (CLA), Cu, direct-fed microbials (DFM), carbohydrases, proteases, phytases, multi-enzymes, essential oils (EO), L-carnitine, yeasts, and Zn. Research articles were collected from online research databases. Inclusion and exclusion criteria were utilized to select qualified research articles. The percentage difference for each response variable between the treatment and control group was calculated and summarized to determine the expected magnitude of effect. Most of the results showed positive outcomes for each feed additive; however, the magnitude of improvement varied, and most were not statistically significant. For ADG, DFM, Cu, L-carnitine, and multi-enzymes showed relatively large and positive effects across a reasonable number of research articles. Acidifiers, betaine, CLA, multi-enzymes, DFM, L-carnitine, and yeasts showed relatively large and positive effects on improving G:F. Moreover, except for betaine, Cr, CLA, and L-carnitine, most feed additives showed little and non-significant effects on carcass characteristics.