Health care resource utilization (HCRU) and direct costs incurred over 12 months following initiation of galcanezumab (GMB) or standard-of-care (SOC) preventive migraine treatments have been evaluated. However, a gap in knowledge exists in understanding longer-term HCRU and direct costs. To compare all-cause and migraine-related HCRU and direct costs in patients with migraine initiating GMB or SOC preventive migraine treatments over a 24-month follow-up. This retrospective study used Optum deidentified Market Clarity Data. The study included adults diagnosed with migraine, with at least 1 claim for GMB or SOC preventive migraine therapy (September 2018 to March 2020), with continuous enrollment for 12 months before and 24 months after (follow-up) the index date (date of first GMB or SOC claim). Propensity score (PS) matching (1:1) was used to balance cohorts. All-cause and migraine-related HCRU and direct costs for GMB vs SOC cohorts were reported as mean (SD) per patient per year (PPPY) over a 24-month follow-up and compared using a Z-test. Costs were inflated to 2022 US$. After PS matching, 2,307 patient pairs (mean age: 44.4 years; female sex: 87.3%) were identified. Compared with the SOC cohort, the GMB cohort had lower mean (SD) PPPY all-cause office visits (17.9 [17.7] vs 19.1 [18.7]; P = 0.023) and migraine-related office visits (2.6 [3.3] vs 3.0 [4.7]; P = 0.002) at follow-up. No significant differences were observed between cohorts in other all-cause and migraine-related events assessed including outpatient visits, emergency department (ED) visits, inpatient stays, and other medical visits. The mean (SD) costs PPPY were lower in the GMB cohort compared with the SOC cohort for all-cause office visits ($4,321 [7,518] vs $5,033 [7,211]; P < 0.001) at follow-up. However, the GMB cohort had higher mean (SD) PPPY all-cause total costs ($24,704 [30,705] vs $21,902 [28,213]; P = 0.001) and pharmacy costs ($9,507 [12,659] vs $5,623 [12,605]; P < 0.001) compared with the SOC cohort. Mean (SD) costs PPPY were lower in the GMB cohort for migraine-related office visits ($806 [1,690] vs $1,353 [2,805]; P < 0.001) compared with the SOC cohort. However, the GMB cohort had higher mean (SD) PPPY migraine-related total costs ($8,248 [11,486] vs $5,047 [9,749]; P < 0.001) and migraine-related pharmacy costs ($5,394 [3,986] vs $1,761 [4,133]; P < 0.001) compared with the SOC cohort. There were no significant differences between cohorts in all-cause and migraine-related costs for outpatient visits, ED visits, inpatient stays, and other medical visits. Although total costs were greater for GMB vs SOC following initiation, changes in a few categories of all-cause and migraine-related HCRU and direct costs were lower for GMB over a 24-month follow-up. Additional analysis evaluating indirect health care costs may offer insights into further cost savings incurred with preventive migraine treatment.