With the increased availability of daily milk yield measurements, data exists for analyses of additional traits that could be related to health and fertility. Selection for milk yield variability would be feasible if cows with more consistent milk yield exhibit greater levels of fertility or health. The objective of this study was to determine if day-to-day variation in milk yield is heritable and how it is correlated with daily milk yield (dMY). We retrieved 789,266 dMY records from 5 to 250 d in milk for 2366 lactations of 1184 Holsteins; of these, 470 had 42K genotypes. We merged dMY with the previous day’s milk yield (pMY) to derive the absolute value of dMY − pMY (ΔABS), and relative change in milk yield (ΔREL), which was ΔABS/pMY. Only lactations with at least 200 observations were retained, and the average ΔREL, ΔABS, and pMY for the first 250 d of lactation were calculated and included in a 3-trait single-step genomic evaluation in ASReml. The fixed effects included lactation group (lactations 1, 2, ≥3), age at calving, and year-season of calving, and the random effects encompassed the genomic relationship effect, permanent environment, and residual error. Pedigree and genotypic data were blended to create the genomic relationship matrix with PREGSF90. All traits were heritable with estimates of 0.23 ± 0.04, 0.15 ± 0.04, and 0.26 ± 0.05 for ΔABS, ΔREL, and pMY, respectively. The genetic correlation estimate between ΔABS and pMY was 0.76 ± 0.07, whereas the genetic correlation estimate between ΔREL, and pMY was −0.15 ± 0.16. The phenotypic correlation estimates of pMY with ΔABS and ΔREL were 0.60 ± 0.02 and −0.32 ± 0.02, respectively. The 2 measures of variability were moderately correlated with a genetic correlation estimate of 0.52 ± 0.12 and phenotypic correlation estimate of 0.52 ± 0.02. Last, repeatabilities ranged from 0.32 ± 0.03 (ΔREL) to 0.41 ± 0.03 (pMY). In conclusion, daily milk yield variability was heritable and ΔREL was more independent of milk yield than ΔABS.