diff --git a/apps/oxlint/test/lsp/utils.ts b/apps/oxlint/test/lsp/utils.ts
index 534c2adb820b3..1373522728743 100644
--- a/apps/oxlint/test/lsp/utils.ts
+++ b/apps/oxlint/test/lsp/utils.ts
@@ -27,6 +27,17 @@ import { codeFrameColumns } from "@babel/code-frame";
 
 const CLI_PATH = join(import.meta.dirname, "..", "..", "dist", "cli.js");
 
+const PULL_DIAGNOSTICS_CAPABILITY = {
+  textDocument: {
+    diagnostic: {},
+  },
+  workspace: {
+    diagnostics: {
+      refreshSupport: true,
+    },
+  },
+};
+
 export function createLspConnection() {
   const proc = spawn(process.execPath, [CLI_PATH, "--lsp"], {
     env: {
@@ -110,32 +121,64 @@ export async function lintFixture(
   languageId: string,
   initializationOptions?: OxlintLSPConfig,
 ): Promise<string> {
-  const filePath = join(fixturesDir, fixturePath);
-  const dirPath = dirname(filePath);
-  const fileUri = pathToFileURL(filePath).href;
-  const content = await fs.readFile(filePath, "utf-8");
+  return lintMultiWorkspaceFixture(
+    fixturesDir,
+    [{ path: fixturePath, languageId }],
+    initializationOptions ? [initializationOptions] : undefined,
+  );
+}
 
+export async function lintMultiWorkspaceFixture(
+  fixturesDir: string,
+  fixturePaths: {
+    path: string;
+    languageId: string;
+  }[],
+  initializationOptions?: OxlintLSPConfig[],
+): Promise<string> {
+  const workspaceUris = fixturePaths.map(
+    ({ path }) => pathToFileURL(dirname(join(fixturesDir, path))).href,
+  );
   await using client = createLspConnection();
 
   await client.initialize(
-    [{ uri: pathToFileURL(dirPath).href, name: "test" }],
-    {
-      textDocument: {
-        diagnostic: {},
-      },
-      workspace: {
-        diagnostics: {
-          refreshSupport: true,
-        },
-      },
-    },
-    [
-      {
-        workspaceUri: pathToFileURL(dirPath).href,
-        options: initializationOptions,
-      },
-    ],
+    workspaceUris.map((uri, index) => ({ uri, name: `workspace-${index}` })),
+    PULL_DIAGNOSTICS_CAPABILITY,
+    workspaceUris.map((workspaceUri, index) => ({
+      workspaceUri,
+      options: initializationOptions?.[index] ?? null,
+    })),
   );
+
+  const snapshots = [];
+  for (const fixturePath of fixturePaths) {
+    snapshots.push(
+      // oxlint-disable-next-line no-await-in-loop -- for snapshot consistency
+      await getDiagnosticSnapshot(
+        fixturePath.path,
+        join(fixturesDir, fixturePath.path),
+        fixturePath.languageId,
+        client,
+      ),
+    );
+  }
+
+  return snapshots.join("\n\n");
+}
+
+// ---
+
+type OxlintLSPConfig = {};
+
+async function getDiagnosticSnapshot(
+  fixturePath: string,
+  filePath: string,
+  languageId: string,
+  client: ReturnType<typeof createLspConnection>,
+): Promise<string> {
+  const fileUri = pathToFileURL(filePath).href;
+  const content = await fs.readFile(filePath, "utf-8");
+
   await client.didOpen(fileUri, languageId, content);
 
   const diagnostics = await client.diagnostic(fileUri);
@@ -149,10 +192,6 @@ ${applyDiagnostics(content, diagnostics).join("\n--------------------")}
 `.trim();
 }
 
-// ---
-
-type OxlintLSPConfig = {};
-
 function getSeverityLabel(severity: number | undefined): string {
   if (!severity) return "Unknown";
 
diff --git a/apps/oxlint/test/lsp/workspaces/__snapshots__/workspace.test.ts.snap b/apps/oxlint/test/lsp/workspaces/__snapshots__/workspace.test.ts.snap
new file mode 100644
index 0000000000000..6d1dc79821805
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/__snapshots__/workspace.test.ts.snap
@@ -0,0 +1,73 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`LSP multi workspace linting > basic linting > should handle { path: 'config-default-both/workspace1/test.ts', languageId: 'typescript' } 1`] = `
+"--- FILE -----------
+config-default-both/workspace1/test.ts
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Warning: \`debugger\` statement is not allowed
+help: Remove the debugger statement
+--------------------
+
+--- FILE -----------
+config-default-both/workspace2/test.ts
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Warning: \`debugger\` statement is not allowed
+help: Remove the debugger statement
+--------------------"
+`;
+
+exports[`LSP multi workspace linting > basic linting > should handle { path: 'default-both/workspace1/test.ts', languageId: 'typescript' } 1`] = `
+"--- FILE -----------
+default-both/workspace1/test.ts
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Warning: \`debugger\` statement is not allowed
+help: Remove the debugger statement
+--------------------
+
+--- FILE -----------
+default-both/workspace2/test.ts
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Warning: \`debugger\` statement is not allowed
+help: Remove the debugger statement
+--------------------"
+`;
+
+exports[`LSP multi workspace linting > basic linting > should handle { path: 'different-js-plugin/workspace1/test.js', languageId: 'javascript' } 1`] = `
+"--- FILE -----------
+different-js-plugin/workspace1/test.js
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Error: Workspace 1 Plugin
+  2 |
+--------------------
+
+--- FILE -----------
+different-js-plugin/workspace2/test.js
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Error: Workspace 2 Plugin
+  2 |
+--------------------"
+`;
+
+exports[`LSP multi workspace linting > basic linting > should handle { path: 'different-severity/workspace1/test.ts', languageId: 'typescript' } 1`] = `
+"--- FILE -----------
+different-severity/workspace1/test.ts
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Error: \`debugger\` statement is not allowed
+help: Remove the debugger statement
+--------------------
+
+--- FILE -----------
+different-severity/workspace2/test.ts
+--- Diagnostics ---------
+> 1 | debugger;
+    | ^^^^^^^^^ Warning: \`debugger\` statement is not allowed
+help: Remove the debugger statement
+--------------------"
+`;
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace1/.oxlintrc.json b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace1/.oxlintrc.json
new file mode 100644
index 0000000000000..2c63c0851048d
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace1/.oxlintrc.json
@@ -0,0 +1,2 @@
+{
+}
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace1/test.ts b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace1/test.ts
new file mode 100644
index 0000000000000..9f5fb105ad0c2
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace1/test.ts
@@ -0,0 +1 @@
+debugger;
\ No newline at end of file
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace2/.oxlintrc.json b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace2/.oxlintrc.json
new file mode 100644
index 0000000000000..2c63c0851048d
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace2/.oxlintrc.json
@@ -0,0 +1,2 @@
+{
+}
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace2/test.ts b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace2/test.ts
new file mode 100644
index 0000000000000..9f5fb105ad0c2
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/config-default-both/workspace2/test.ts
@@ -0,0 +1 @@
+debugger;
\ No newline at end of file
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/default-both/workspace1/test.ts b/apps/oxlint/test/lsp/workspaces/fixtures/default-both/workspace1/test.ts
new file mode 100644
index 0000000000000..9f5fb105ad0c2
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/default-both/workspace1/test.ts
@@ -0,0 +1 @@
+debugger;
\ No newline at end of file
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/default-both/workspace2/test.ts b/apps/oxlint/test/lsp/workspaces/fixtures/default-both/workspace2/test.ts
new file mode 100644
index 0000000000000..9f5fb105ad0c2
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/default-both/workspace2/test.ts
@@ -0,0 +1 @@
+debugger;
\ No newline at end of file
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/.oxlintrc.json b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/.oxlintrc.json
new file mode 100644
index 0000000000000..6a2c6b1f6a1b8
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/.oxlintrc.json
@@ -0,0 +1,7 @@
+{
+  "jsPlugins": ["./plugin.js"],
+  "rules": {
+    "js-plugin/test-rule": "error",
+    "no-debugger": "off",
+  }
+}
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/plugin.js b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/plugin.js
new file mode 100644
index 0000000000000..c83227f032333
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/plugin.js
@@ -0,0 +1,22 @@
+const plugin = {
+  meta: {
+    name: 'js-plugin',
+  },
+  rules: {
+    'test-rule': {
+      create(context) {
+        return {
+          DebuggerStatement(debuggerStatement) {
+            context.report({
+              message: 'Workspace 1 Plugin',
+              node: debuggerStatement,
+            });
+          },
+        };
+      },
+    },
+  },
+};
+
+
+export default plugin;
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/test.js b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/test.js
new file mode 100644
index 0000000000000..eab74692130a6
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace1/test.js
@@ -0,0 +1 @@
+debugger;
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/.oxlintrc.json b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/.oxlintrc.json
new file mode 100644
index 0000000000000..6a2c6b1f6a1b8
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/.oxlintrc.json
@@ -0,0 +1,7 @@
+{
+  "jsPlugins": ["./plugin.js"],
+  "rules": {
+    "js-plugin/test-rule": "error",
+    "no-debugger": "off",
+  }
+}
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/plugin.js b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/plugin.js
new file mode 100644
index 0000000000000..5ca9a3845fb12
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/plugin.js
@@ -0,0 +1,22 @@
+const plugin = {
+  meta: {
+    name: 'js-plugin',
+  },
+  rules: {
+    'test-rule': {
+      create(context) {
+        return {
+          DebuggerStatement(debuggerStatement) {
+            context.report({
+              message: 'Workspace 2 Plugin',
+              node: debuggerStatement,
+            });
+          },
+        };
+      },
+    },
+  },
+};
+
+
+export default plugin;
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/test.js b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/test.js
new file mode 100644
index 0000000000000..eab74692130a6
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-js-plugin/workspace2/test.js
@@ -0,0 +1 @@
+debugger;
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace1/.oxlintrc.json b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace1/.oxlintrc.json
new file mode 100644
index 0000000000000..a63d73a1442b8
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace1/.oxlintrc.json
@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "no-debugger": "error"
+  }
+}
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace1/test.ts b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace1/test.ts
new file mode 100644
index 0000000000000..9f5fb105ad0c2
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace1/test.ts
@@ -0,0 +1 @@
+debugger;
\ No newline at end of file
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace2/.oxlintrc.json b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace2/.oxlintrc.json
new file mode 100644
index 0000000000000..cfc6c7217e7d1
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace2/.oxlintrc.json
@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "no-debugger": "warn"
+  }
+}
diff --git a/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace2/test.ts b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace2/test.ts
new file mode 100644
index 0000000000000..9f5fb105ad0c2
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/fixtures/different-severity/workspace2/test.ts
@@ -0,0 +1 @@
+debugger;
\ No newline at end of file
diff --git a/apps/oxlint/test/lsp/workspaces/workspace.test.ts b/apps/oxlint/test/lsp/workspaces/workspace.test.ts
new file mode 100644
index 0000000000000..9fdc73fd294bc
--- /dev/null
+++ b/apps/oxlint/test/lsp/workspaces/workspace.test.ts
@@ -0,0 +1,30 @@
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+import { lintMultiWorkspaceFixture } from "../utils";
+
+const FIXTURES_DIR = join(import.meta.dirname, "fixtures");
+
+describe("LSP multi workspace linting", () => {
+  describe("basic linting", () => {
+    it.each([
+      [
+        { path: "default-both/workspace1/test.ts", languageId: "typescript" },
+        { path: "default-both/workspace2/test.ts", languageId: "typescript" },
+      ],
+      [
+        { path: "config-default-both/workspace1/test.ts", languageId: "typescript" },
+        { path: "config-default-both/workspace2/test.ts", languageId: "typescript" },
+      ],
+      [
+        { path: "different-severity/workspace1/test.ts", languageId: "typescript" },
+        { path: "different-severity/workspace2/test.ts", languageId: "typescript" },
+      ],
+      [
+        { path: "different-js-plugin/workspace1/test.js", languageId: "javascript" },
+        { path: "different-js-plugin/workspace2/test.js", languageId: "javascript" },
+      ],
+    ])("should handle %s", async (...paths) => {
+      expect(await lintMultiWorkspaceFixture(FIXTURES_DIR, paths)).toMatchSnapshot();
+    });
+  });
+});