diff --git a/packages/opencode/src/project/project.ts b/packages/opencode/src/project/project.ts
index 1cef41c85c91..3462d7e21cb4 100644
--- a/packages/opencode/src/project/project.ts
+++ b/packages/opencode/src/project/project.ts
@@ -1,7 +1,7 @@
 import z from "zod"
 import { Filesystem } from "../util/filesystem"
 import path from "path"
-import { and, Database, eq } from "../storage/db"
+import { and, Database, eq, sql } from "../storage/db"
 import { ProjectTable } from "./project.sql"
 import { SessionTable } from "../session/session.sql"
 import { Log } from "../util/log"
@@ -276,11 +276,17 @@ export namespace Project {
     // Runs on every startup because sessions created before git init
     // accumulate under "global" and need migrating whenever they appear.
     if (data.id !== ProjectID.global) {
+      // On Windows, use case-insensitive directory matching since the
+      // filesystem is case-insensitive and stored paths may differ in case.
+      const directory =
+        process.platform === "win32"
+          ? sql`LOWER(${SessionTable.directory}) = ${path.normalize(data.worktree).toLowerCase()}`
+          : eq(SessionTable.directory, data.worktree)
       Database.use((db) =>
         db
           .update(SessionTable)
           .set({ project_id: data.id })
-          .where(and(eq(SessionTable.project_id, ProjectID.global), eq(SessionTable.directory, data.worktree)))
+          .where(and(eq(SessionTable.project_id, ProjectID.global), directory))
           .run(),
       )
     }