diff --git a/.changeset/tidy-kiwis-lick.md b/.changeset/tidy-kiwis-lick.md
new file mode 100644
index 000000000000..14a5284dddfa
--- /dev/null
+++ b/.changeset/tidy-kiwis-lick.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixed an issue where spaces and unicode characters in project path prevented middleware from running.
diff --git a/packages/astro/src/core/build/plugins/plugin-middleware.ts b/packages/astro/src/core/build/plugins/plugin-middleware.ts
index 47ff4b863cf3..22d3f795ba89 100644
--- a/packages/astro/src/core/build/plugins/plugin-middleware.ts
+++ b/packages/astro/src/core/build/plugins/plugin-middleware.ts
@@ -25,7 +25,7 @@ export function vitePluginMiddleware(
 		async resolveId(id) {
 			if (id === MIDDLEWARE_MODULE_ID) {
 				const middlewareId = await this.resolve(
-					`${opts.settings.config.srcDir.pathname}/${MIDDLEWARE_PATH_SEGMENT_NAME}`
+					`${decodeURI(opts.settings.config.srcDir.pathname)}${MIDDLEWARE_PATH_SEGMENT_NAME}`
 				);
 				if (middlewareId) {
 					resolvedMiddlewareId = middlewareId.id;
diff --git a/packages/astro/src/core/middleware/loadMiddleware.ts b/packages/astro/src/core/middleware/loadMiddleware.ts
index 9a7f3e4bc4cc..b8528eb4b336 100644
--- a/packages/astro/src/core/middleware/loadMiddleware.ts
+++ b/packages/astro/src/core/middleware/loadMiddleware.ts
@@ -12,7 +12,7 @@ export async function loadMiddleware(
 	srcDir: AstroSettings['config']['srcDir']
 ) {
 	// can't use node Node.js builtins
-	let middlewarePath = srcDir.pathname + '/' + MIDDLEWARE_PATH_SEGMENT_NAME;
+	let middlewarePath = `${decodeURI(srcDir.pathname)}${MIDDLEWARE_PATH_SEGMENT_NAME}`;
 	try {
 		const module = await moduleLoader.import(middlewarePath);
 		return module;
diff --git a/packages/astro/test/featuresSupport.test.js b/packages/astro/test/featuresSupport.test.js
index fba8da47557d..c25d9d5f8f08 100644
--- a/packages/astro/test/featuresSupport.test.js
+++ b/packages/astro/test/featuresSupport.test.js
@@ -8,7 +8,7 @@ describe('Adapter', () => {
 	it("should error if the adapter doesn't support edge middleware", async () => {
 		try {
 			fixture = await loadFixture({
-				root: './fixtures/middleware-dev/',
+				root: './fixtures/middleware space/',
 				output: 'server',
 				build: {
 					excludeMiddleware: true,
@@ -32,7 +32,7 @@ describe('Adapter', () => {
 	it("should error if the adapter doesn't support split build", async () => {
 		try {
 			fixture = await loadFixture({
-				root: './fixtures/middleware-dev/',
+				root: './fixtures/middleware space/',
 				output: 'server',
 				build: {
 					split: true,
diff --git a/packages/astro/test/fixtures/middleware-dev/package.json b/packages/astro/test/fixtures/middleware space/package.json
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/package.json
rename to packages/astro/test/fixtures/middleware space/package.json
diff --git a/packages/astro/test/fixtures/middleware-dev/src/middleware.js b/packages/astro/test/fixtures/middleware space/src/middleware.js
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/middleware.js
rename to packages/astro/test/fixtures/middleware space/src/middleware.js
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/404.astro b/packages/astro/test/fixtures/middleware space/src/pages/404.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/404.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/404.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/api/endpoint.js b/packages/astro/test/fixtures/middleware space/src/pages/api/endpoint.js
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/api/endpoint.js
rename to packages/astro/test/fixtures/middleware space/src/pages/api/endpoint.js
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/broken-500.astro b/packages/astro/test/fixtures/middleware space/src/pages/broken-500.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/broken-500.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/broken-500.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/broken-locals.astro b/packages/astro/test/fixtures/middleware space/src/pages/broken-locals.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/broken-locals.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/broken-locals.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/clone.astro b/packages/astro/test/fixtures/middleware space/src/pages/clone.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/clone.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/clone.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/does-nothing.astro b/packages/astro/test/fixtures/middleware space/src/pages/does-nothing.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/does-nothing.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/does-nothing.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/index.astro b/packages/astro/test/fixtures/middleware space/src/pages/index.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/index.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/index.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/lorem.astro b/packages/astro/test/fixtures/middleware space/src/pages/lorem.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/lorem.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/lorem.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/not-interested.astro b/packages/astro/test/fixtures/middleware space/src/pages/not-interested.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/not-interested.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/not-interested.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/redirect.astro b/packages/astro/test/fixtures/middleware space/src/pages/redirect.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/redirect.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/redirect.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/rewrite.astro b/packages/astro/test/fixtures/middleware space/src/pages/rewrite.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/rewrite.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/rewrite.astro
diff --git a/packages/astro/test/fixtures/middleware-dev/src/pages/second.astro b/packages/astro/test/fixtures/middleware space/src/pages/second.astro
similarity index 100%
rename from packages/astro/test/fixtures/middleware-dev/src/pages/second.astro
rename to packages/astro/test/fixtures/middleware space/src/pages/second.astro
diff --git a/packages/astro/test/middleware.test.js b/packages/astro/test/middleware.test.js
index 9ca4841d4e4e..81f167647b59 100644
--- a/packages/astro/test/middleware.test.js
+++ b/packages/astro/test/middleware.test.js
@@ -12,7 +12,7 @@ describe('Middleware in DEV mode', () => {
 
 	before(async () => {
 		fixture = await loadFixture({
-			root: './fixtures/middleware-dev/',
+			root: './fixtures/middleware space/',
 		});
 		devServer = await fixture.startDevServer();
 	});
@@ -116,7 +116,7 @@ describe('Middleware API in PROD mode, SSR', () => {
 
 	before(async () => {
 		fixture = await loadFixture({
-			root: './fixtures/middleware-dev/',
+			root: './fixtures/middleware space/',
 			output: 'server',
 			adapter: testAdapter({}),
 		});
@@ -223,7 +223,7 @@ describe('Middleware API in PROD mode, SSR', () => {
 
 	it('the integration should receive the path to the middleware', async () => {
 		fixture = await loadFixture({
-			root: './fixtures/middleware-dev/',
+			root: './fixtures/middleware space/',
 			output: 'server',
 			build: {
 				excludeMiddleware: true,
@@ -275,7 +275,7 @@ describe('Middleware, split middleware option', () => {
 
 	before(async () => {
 		fixture = await loadFixture({
-			root: './fixtures/middleware-dev/',
+			root: './fixtures/middleware space/',
 			output: 'server',
 			build: {
 				excludeMiddleware: true,
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 1aebf6930f4c..eb5e684fa34b 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -2847,7 +2847,7 @@ importers:
         specifier: workspace:*
         version: link:../../..
 
-  packages/astro/test/fixtures/middleware-dev:
+  packages/astro/test/fixtures/middleware space:
     dependencies:
       astro:
         specifier: workspace:*