diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java b/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java
index 5d9df8b10..90d9e5d8e 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java
@@ -427,7 +427,7 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
 
     environment.jersey().register(new TimestampResponseFilter());
 
-    environment.jersey().register(new AccountController(pendingAccountsManager, accountsManager, usernamesManager, abusiveHostRules, rateLimiters, smsSender, directoryQueue, messagesManager, turnTokenGenerator, config.getTestDevices(), recaptchaClient, gcmSender, apnSender, backupCredentialsGenerator));
+    environment.jersey().register(new AccountController(pendingAccountsManager, accountsManager, usernamesManager, abusiveHostRules, rateLimiters, smsSender, directoryQueue, messagesManager, dynamicConfigurationManager, turnTokenGenerator, config.getTestDevices(), recaptchaClient, gcmSender, apnSender, backupCredentialsGenerator));
     environment.jersey().register(new DeviceController(pendingDevicesManager, accountsManager, messagesManager, directoryQueue, rateLimiters, config.getMaxDevices()));
     environment.jersey().register(new DirectoryController(directoryCredentialsGenerator));
     environment.jersey().register(new ProvisioningController(rateLimiters, provisioningManager));
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfiguration.java b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfiguration.java
index 0aa94779b..5d9ffd57f 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfiguration.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfiguration.java
@@ -41,6 +41,9 @@ public class DynamicConfiguration {
   @Valid
   private DynamicTwilioConfiguration twilio = new DynamicTwilioConfiguration();
 
+  @JsonProperty
+  private DynamicSignupCaptchaConfiguration signupCaptcha = new DynamicSignupCaptchaConfiguration();
+
   public Optional<DynamicExperimentEnrollmentConfiguration> getExperimentEnrollmentConfiguration(
       final String experimentName) {
     return Optional.ofNullable(experiments.get(experimentName));
@@ -80,4 +83,7 @@ public class DynamicConfiguration {
     this.twilio = twilioConfiguration;
   }
 
+  public DynamicSignupCaptchaConfiguration getSignupCaptchaConfiguration() {
+    return signupCaptcha;
+  }
 }
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicSignupCaptchaConfiguration.java b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicSignupCaptchaConfiguration.java
new file mode 100644
index 000000000..894b7f370
--- /dev/null
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicSignupCaptchaConfiguration.java
@@ -0,0 +1,23 @@
+package org.whispersystems.textsecuregcm.configuration.dynamic;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.annotations.VisibleForTesting;
+import java.util.Collections;
+import java.util.Set;
+import javax.validation.constraints.NotNull;
+
+public class DynamicSignupCaptchaConfiguration {
+
+  @JsonProperty
+  @NotNull
+  private Set<String> countryCodes = Collections.emptySet();
+
+  public Set<String> getCountryCodes() {
+    return countryCodes;
+  }
+
+  @VisibleForTesting
+  public void setCountryCodes(Set<String> numbers) {
+    this.countryCodes = numbers;
+  }
+}
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
index 34adab367..11bb31155 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
@@ -16,7 +16,6 @@ import io.micrometer.core.instrument.Metrics;
 import io.micrometer.core.instrument.Tag;
 import java.security.SecureRandom;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
@@ -48,6 +47,7 @@ import org.whispersystems.textsecuregcm.auth.StoredRegistrationLock;
 import org.whispersystems.textsecuregcm.auth.StoredVerificationCode;
 import org.whispersystems.textsecuregcm.auth.TurnToken;
 import org.whispersystems.textsecuregcm.auth.TurnTokenGenerator;
+import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicSignupCaptchaConfiguration;
 import org.whispersystems.textsecuregcm.entities.AccountAttributes;
 import org.whispersystems.textsecuregcm.entities.AccountCreationResult;
 import org.whispersystems.textsecuregcm.entities.ApnRegistrationId;
@@ -70,6 +70,7 @@ import org.whispersystems.textsecuregcm.storage.AbusiveHostRules;
 import org.whispersystems.textsecuregcm.storage.Account;
 import org.whispersystems.textsecuregcm.storage.AccountsManager;
 import org.whispersystems.textsecuregcm.storage.Device;
+import org.whispersystems.textsecuregcm.storage.DynamicConfigurationManager;
 import org.whispersystems.textsecuregcm.storage.MessagesManager;
 import org.whispersystems.textsecuregcm.storage.PendingAccountsManager;
 import org.whispersystems.textsecuregcm.storage.UsernamesManager;
@@ -111,6 +112,7 @@ public class AccountController {
   private final SmsSender                          smsSender;
   private final DirectoryQueue                     directoryQueue;
   private final MessagesManager                    messagesManager;
+  private final DynamicConfigurationManager        dynamicConfigurationManager;
   private final TurnTokenGenerator                 turnTokenGenerator;
   private final Map<String, Integer>               testDevices;
   private final RecaptchaClient                    recaptchaClient;
@@ -126,6 +128,7 @@ public class AccountController {
                            SmsSender smsSenderFactory,
                            DirectoryQueue directoryQueue,
                            MessagesManager messagesManager,
+                           DynamicConfigurationManager dynamicConfigurationManager,
                            TurnTokenGenerator turnTokenGenerator,
                            Map<String, Integer> testDevices,
                            RecaptchaClient recaptchaClient,
@@ -141,6 +144,7 @@ public class AccountController {
     this.smsSender                         = smsSenderFactory;
     this.directoryQueue                    = directoryQueue;
     this.messagesManager                   = messagesManager;
+    this.dynamicConfigurationManager       = dynamicConfigurationManager;
     this.testDevices                       = testDevices;
     this.turnTokenGenerator                = turnTokenGenerator;
     this.recaptchaClient                   = recaptchaClient;
@@ -590,9 +594,10 @@ public class AccountController {
       }
     }
 
+    final String countryCode = Util.getCountryCode(number);
     {
       final List<Tag> tags = new ArrayList<>();
-      tags.add(Tag.of(COUNTRY_CODE_TAG_NAME, Util.getCountryCode(number)));
+      tags.add(Tag.of(COUNTRY_CODE_TAG_NAME, countryCode));
 
       try {
         if (pushChallenge.isPresent()) {
@@ -650,6 +655,11 @@ public class AccountController {
       return new CaptchaRequirement(true, true);
     }
 
+    DynamicSignupCaptchaConfiguration signupCaptchaConfig = dynamicConfigurationManager.getConfiguration().getSignupCaptchaConfiguration();
+    if (signupCaptchaConfig.getCountryCodes().contains(countryCode)) {
+      return new CaptchaRequirement(true, false);
+    }
+
     return new CaptchaRequirement(false, false);
   }
 
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfigurationTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfigurationTest.java
index c21b261ae..daf088a4e 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfigurationTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfigurationTest.java
@@ -276,4 +276,28 @@ class DynamicConfigurationTest {
       assertEquals(Set.of("44"), config.getAllowedCountryCodes());
     }
   }
+
+  @Test
+  public void testParseSignupCaptchaConfiguration() throws JsonProcessingException {
+    {
+      final String emptyConfigYaml = "test: true";
+      final DynamicConfiguration emptyConfig = DynamicConfigurationManager.OBJECT_MAPPER
+          .readValue(emptyConfigYaml, DynamicConfiguration.class);
+
+      assertTrue(emptyConfig.getSignupCaptchaConfiguration().getCountryCodes().isEmpty());
+    }
+
+    {
+      final String signupCaptchaConfig =
+          "signupCaptcha:\n"
+              + "  countryCodes:\n"
+              + "    - 1";
+
+      final DynamicSignupCaptchaConfiguration config = DynamicConfigurationManager.OBJECT_MAPPER
+          .readValue(signupCaptchaConfig, DynamicConfiguration.class)
+          .getSignupCaptchaConfiguration();
+
+      assertEquals(Set.of("1"), config.getCountryCodes());
+    }
+  }
 }
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AccountControllerTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AccountControllerTest.java
index 87fe99912..c9d8c3263 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AccountControllerTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AccountControllerTest.java
@@ -32,8 +32,10 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Optional;
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Stream;
 import javax.ws.rs.client.Entity;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
@@ -43,7 +45,9 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.MethodSource;
 import org.mockito.ArgumentCaptor;
 import org.mockito.ArgumentMatcher;
 import org.whispersystems.textsecuregcm.auth.AuthenticationCredentials;
@@ -52,6 +56,8 @@ import org.whispersystems.textsecuregcm.auth.ExternalServiceCredentialGenerator;
 import org.whispersystems.textsecuregcm.auth.StoredRegistrationLock;
 import org.whispersystems.textsecuregcm.auth.StoredVerificationCode;
 import org.whispersystems.textsecuregcm.auth.TurnTokenGenerator;
+import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfiguration;
+import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicSignupCaptchaConfiguration;
 import org.whispersystems.textsecuregcm.controllers.AccountController;
 import org.whispersystems.textsecuregcm.controllers.RateLimitExceededException;
 import org.whispersystems.textsecuregcm.entities.AccountAttributes;
@@ -75,6 +81,7 @@ import org.whispersystems.textsecuregcm.storage.AbusiveHostRule;
 import org.whispersystems.textsecuregcm.storage.AbusiveHostRules;
 import org.whispersystems.textsecuregcm.storage.Account;
 import org.whispersystems.textsecuregcm.storage.AccountsManager;
+import org.whispersystems.textsecuregcm.storage.DynamicConfigurationManager;
 import org.whispersystems.textsecuregcm.storage.MessagesManager;
 import org.whispersystems.textsecuregcm.storage.PendingAccountsManager;
 import org.whispersystems.textsecuregcm.storage.UsernamesManager;
@@ -130,6 +137,8 @@ class AccountControllerTest {
   private static APNSender              apnSender              = mock(APNSender.class);
   private static UsernamesManager       usernamesManager       = mock(UsernamesManager.class);
 
+  private static DynamicConfigurationManager dynamicConfigurationManager = mock(DynamicConfigurationManager.class);
+
   private byte[] registration_lock_key = new byte[32];
   private static ExternalServiceCredentialGenerator storageCredentialGenerator = new ExternalServiceCredentialGenerator(new byte[32], new byte[32], false);
 
@@ -148,6 +157,7 @@ class AccountControllerTest {
                                                                                                smsSender,
                                                                                                directoryQueue,
                                                                                                storedMessages,
+                                                                                               dynamicConfigurationManager,
                                                                                                turnTokenGenerator,
                                                                                                new HashMap<>(),
                                                                                                recaptchaClient,
@@ -207,6 +217,15 @@ class AccountControllerTest {
     when(usernamesManager.put(eq(AuthHelper.VALID_UUID), eq("n00bkiller"))).thenReturn(true);
     when(usernamesManager.put(eq(AuthHelper.VALID_UUID), eq("takenusername"))).thenReturn(false);
 
+    {
+      DynamicConfiguration dynamicConfiguration = mock(DynamicConfiguration.class);
+      when(dynamicConfigurationManager.getConfiguration())
+          .thenReturn(dynamicConfiguration);
+
+      DynamicSignupCaptchaConfiguration signupCaptchaConfig = new DynamicSignupCaptchaConfiguration();
+
+      when(dynamicConfiguration.getSignupCaptchaConfiguration()).thenReturn(signupCaptchaConfig);
+    }
     when(abusiveHostRules.getAbusiveHostRulesFor(eq(ABUSIVE_HOST))).thenReturn(Collections.singletonList(new AbusiveHostRule(ABUSIVE_HOST, true, Collections.emptyList())));
     when(abusiveHostRules.getAbusiveHostRulesFor(eq(RESTRICTED_HOST))).thenReturn(Collections.singletonList(new AbusiveHostRule(RESTRICTED_HOST, false, Collections.singletonList("+123"))));
     when(abusiveHostRules.getAbusiveHostRulesFor(eq(NICE_HOST))).thenReturn(Collections.emptyList());
@@ -1275,4 +1294,38 @@ class AccountControllerTest {
     assertThat(response.getStatus()).isEqualTo(204);
     verify(accountsManager).delete(AuthHelper.VALID_ACCOUNT, AccountsManager.DeletionReason.USER_REQUEST);
   }
+
+  @ParameterizedTest
+  @MethodSource
+  void testSignupCaptcha(final String message, final boolean enforced, final Set<String> countryCodes, final int expectedResponseStatusCode) {
+    DynamicConfiguration dynamicConfiguration = mock(DynamicConfiguration.class);
+    when(dynamicConfigurationManager.getConfiguration())
+        .thenReturn(dynamicConfiguration);
+
+    DynamicSignupCaptchaConfiguration signupCaptchaConfig = new DynamicSignupCaptchaConfiguration();
+    signupCaptchaConfig.setCountryCodes(countryCodes);
+    when(dynamicConfiguration.getSignupCaptchaConfiguration())
+        .thenReturn(signupCaptchaConfig);
+
+    Response response =
+        resources.getJerseyTest()
+            .target(String.format("/v1/accounts/sms/code/%s", SENDER))
+            .queryParam("challenge", "1234-push")
+            .request()
+            .header("X-Forwarded-For", NICE_HOST)
+            .get();
+
+    assertThat(response.getStatus()).isEqualTo(expectedResponseStatusCode);
+
+    verify(smsSender, 200 == expectedResponseStatusCode ? times(1) : never())
+        .deliverSmsVerification(eq(SENDER), eq(Optional.empty()), anyString());
+  }
+
+  static Stream<Arguments> testSignupCaptcha() {
+    return Stream.of(
+        Arguments.of("captcha not enforced", false, Collections.emptySet(), 200),
+        Arguments.of("no enforced country codes", true, Collections.emptySet(), 200),
+        Arguments.of("captcha enforced", true, Set.of("1"), 402)
+    );
+  }
 }