The objective was to determine effects of increasing grass hay (GH) inclusion level on weaned dairy calf growth and metabolism. Holstein calves (n = 45) were randomly assigned to 1 of 3 total mixed rations (TMR) with increasing GH (10%, 17.5%, or 25% on a dry matter (DM) basis; LGH, MGH, or HGH respectively). Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of texturized calf starter (20% crude protein) and chopped GH, were offered ad libitum as separate components from 7 to 9 wk of age. After 9 wk, feed was offered ad libitum as a TMR containing the assigned level of GH. Initial 9-wk body weight (BW) was 81.6 ± 9 kg. Intake and growth were measured weekly. Blood samples were collected at 9, 10, 12, 14, and 16 wk of age. Total fecal collection (12 calves) was conducted for 4 d at 11 and 15 wk of age. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to estimate total-tract digestibility. The statistical model included initial 9-wk BW as a covariate, fixed effect of TMR, random effects of calf, week of study, and sex, and repeated effects of age. Linear and quadratic responses were tested using orthogonal polynomial contrasts. Final BW decreased linearly with increased GH (P < 0.01), but frame measurements did not vary between groups. Intake and weight gain were analyzed from 7 to 9 wk and 9 to 16 wk, representing pretreatment and treatment periods. There were no differences between groups from 7 to 9 wk. However, differences were found from 9 to 16 wk. Average daily gain, DM intake, and metabolizable energy intake all decreased linearly with increased GH (P < 0.01). Plasma β-hydroxybutyrate tended to decrease with increased GH (P = 0.07). There were no differences in DM or starch digestibility, but neutral detergent fiber and acid detergent fiber digestibility increased linearly with increased GH (P < 0.01 and P = 0.06 respectively). Levels of GH > 10% may reduce intake and growth before 16 wk.