Dietary fiber can provide functional benefits to nursery pigs, thereby improving gut health and growth performance. However, effects vary depending on the type and amount of fiber supplemented. The objective of this experiment was to determine the effects of dietary fermentable fiber (FRM), structural fiber (STR), and their interaction on growth performance of nursery pigs. In total, 3,014 weanling pigs (body weight = 5.71 ± 0.11 kg, 15 replicate pens/treatment, 21 – 23 pigs/pen) were allotted by pen in a randomized complete block design to treatments in a 3 × 3 factorial arrangement with 2 factors: FRM (12, 13, or 14%) and STR (3, 4, or 5%). Diets were formulated to maintain similar dietary protein and metabolizable energy, and rice hulls or beet pulp were added to achieve different levels of STR and FRM, respectively. Fiber concentrations were estimated using in vitro fermentation methods. Phase 1 and 2 diets were fed from day 0 – 11 and 11 – 21 post-weaning, respectively. A common diet was fed from day 21 – 43. Data were analyzed by general linear model in R with random effect of location block. Orthogonal contrasts tested for linear and quadratic effects of STR and FRM, and their interaction. Overall (day 0 – 43), increasing FRM increased average daily gain (ADG; linear, P < 0.05). As STR increased, overall ADG increased and then decreased (quadratic, P < 0.05), with 4% STR resulting in the greatest ADG. Interactions between fiber type were observed (P < 0.05) for final body weight, overall average daily feed intake, and overall gain:feed.