Background and objectives.White matter hyperintensities (WMH) are frequent imaging features of small vessel disease (SVD) and related to poor clinical outcomes. WMH progression over time is well described, but regression was also noted recently, although the frequency and associated factors are unknown. This systematic review and meta-analysis aims to assess longitudinal intra-individual WMH volume changes in sporadic SVD.Methods.We searched EMBASE and MEDLINE for papers up to 28 January 2022 on WMH volume changes using MRI on ≥2 time-points in adults with sporadic SVD. We classified populations (healthy/community-dwelling, stroke, cognitive, other vascular risk factors, depression) based on study characteristics. We performed random-effects meta-analyses with Knapp-Hartung adjustment to determine mean WMH volume change (change in mL, % of intracranial volume [%ICV], or mL/year), 95%CI and prediction intervals (PI, limits of increase and decrease) using unadjusted data. Risk of Bias Assessment tool for Non-randomised Studies (RoBANS) was used to assess risk of bias. We followed PRISMA guidelines.Results.Fortyone papers, 12,284 participants, met the inclusion criteria. Thirteen papers had low risk of bias across all domains. Mean WMH volume increased over time by: 1.74 mL (95% CI 1.23, 2.26; PI -1.24, 4.73 mL; 27 papers, N=7411, mean time interval 2.7 years, SD=1.65); 0.25%ICV (95% CI 0.14, 0.36; PI -0.06, 0.56; 6 papers, N=1071, mean time interval 3.5 years, SD =1.54); or 0.58 mL/year (95% CI 0.35, 0.81; PI -0.26, 1.41; 8 papers, N=3802). Additionally, 13 papers specifically mentioned and/or provided data on WMH regression, which occurred in asymptomatic, stroke, and cognitive disorders related to SVD.Discussion.Net mean WMH volume increases over time mask wide-ranging change (e.g. mean increase of 1¾mL ranging from 1¼mL decrease to 4¾ml increase), with regression documented explicitly in up to 1/3 of participants. More knowledge on underlying mechanisms, associated factors and clinical correlates is needed, as WMH regression could be an important intervention target.