Shunt-dependent hydrocephalus (SDHC) is a delayed complication of aneurysmal subarachnoid hemorrhage (SAH), and meningeal fibrotic remodeling may contribute to its development. Secreted protein acidic and rich in cysteine (SPARC) regulates collagen processing and extracellular matrix organization. We examined whether serial plasma SPARC concentrations were associated with subsequent SDHC development. We retrospectively analyzed prospectively collected data from 186 patients with aneurysmal SAH enrolled in a multicenter registry. Plasma SPARC was measured at days 1–3, 4–6, 7–9, and 10–12 and analyzed using log-scale linear mixed-effects models. SDHC developed in 54 patients (29.0%). Model-estimated SPARC concentrations increased across periods in both SDHC and no-SDHC groups without a significant SDHC-by-period interaction, whereas all the SDHC/no-SDHC geometric mean ratios were below 1. The clearest difference occurred at days 4–6 and remained significant after adjustment for age, admission World Federation of Neurological Surgeons grade V, modified Fisher grade 4, and acute hydrocephalus (geometric mean ratio, 0.73; 95% confidence interval, 0.57–0.93; Holm-adjusted p = 0.040). In a post hoc exploratory multivariable analysis, each 10 ng/mL increase in SPARC at days 4–6 was associated with lower odds of subsequent SDHC development (adjusted odds ratio, 0.91; 95% confidence interval, 0.84–0.98; p = 0.011). Lower plasma SPARC concentrations, particularly at days 4–6, were associated with subsequent SDHC development.