diff --git a/android-ech/build.gradle.kts b/android-ech/build.gradle.kts
index 28bcb63..6b98bee 100644
--- a/android-ech/build.gradle.kts
+++ b/android-ech/build.gradle.kts
@@ -33,7 +33,9 @@ android {
   defaultConfig {
     minSdk = 21
 
-    testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    // An AndroidJUnitRunner that calls OkHttp.initialize first. See EchTestRunner for why the
+    // library's own androidx Startup initializer doesn't cover an instrumentation APK.
+    testInstrumentationRunner = "okhttp.testbed.android.ech.EchTestRunner"
     testInstrumentationRunnerArguments +=
       mapOf(
         // The suite is JUnit 5, as the JVM suites are.
diff --git a/android-ech/src/androidTest/kotlin/okhttp/testbed/android/ech/EchTestRunner.kt b/android-ech/src/androidTest/kotlin/okhttp/testbed/android/ech/EchTestRunner.kt
new file mode 100644
index 0000000..541d031
--- /dev/null
+++ b/android-ech/src/androidTest/kotlin/okhttp/testbed/android/ech/EchTestRunner.kt
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2026 OkHttp Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package okhttp.testbed.android.ech
+
+import android.app.Application
+import androidx.test.runner.AndroidJUnitRunner
+import okhttp3.OkHttp
+
+/**
+ * Hands OkHttp the application context before any test runs.
+ *
+ * `okhttp-android` reads the public suffix list from its own assets, and to find them it needs a
+ * `Context`. In an app that context arrives through an androidx Startup `Initializer` declared in
+ * the library's manifest. That doesn't happen here: the library is on the instrumentation APK's
+ * classpath rather than the app's, so nothing runs the initializer and the context is never set.
+ *
+ * What that looks like is not a missing asset — the asset is present — but this, on every test
+ * that resolves a name:
+ *
+ *     java.lang.IllegalStateException: Unable to load PublicSuffixDatabase.list resource.
+ *     Caused by: java.io.IOException: Platform applicationContext not initialized.
+ *         Startup Initializer possibly disabled, call OkHttp.initialize before test.
+ *
+ * `DnsOverHttps` asks `isPrivateHost` about the name before it opens anything, so this throws
+ * before ECH is reached and every case fails for a reason that has nothing to do with ECH.
+ *
+ * Doing it in the runner rather than in a `@BeforeEach` is what makes it true for every suite,
+ * including ones added later, and it happens once rather than per test.
+ */
+class EchTestRunner : AndroidJUnitRunner() {
+  override fun callApplicationOnCreate(app: Application) {
+    super.callApplicationOnCreate(app)
+    OkHttp.initialize(app)
+  }
+}