diff --git a/impl/maven-impl/src/main/java/org/apache/maven/impl/model/DefaultModelBuilder.java b/impl/maven-impl/src/main/java/org/apache/maven/impl/model/DefaultModelBuilder.java
index 298dc260727d..e918edf2a49f 100644
--- a/impl/maven-impl/src/main/java/org/apache/maven/impl/model/DefaultModelBuilder.java
+++ b/impl/maven-impl/src/main/java/org/apache/maven/impl/model/DefaultModelBuilder.java
@@ -69,7 +69,6 @@
 import org.apache.maven.api.model.Model;
 import org.apache.maven.api.model.Parent;
 import org.apache.maven.api.model.Profile;
-import org.apache.maven.api.model.Repository;
 import org.apache.maven.api.services.BuilderProblem;
 import org.apache.maven.api.services.BuilderProblem.Severity;
 import org.apache.maven.api.services.Interpolator;
@@ -498,9 +497,21 @@ public ModelBuilderException newModelBuilderException() {
             return new ModelBuilderException(result);
         }
 
-        public void mergeRepositories(List<Repository> toAdd, boolean replace) {
-            List<RemoteRepository> repos =
-                    toAdd.stream().map(session::createRemoteRepository).toList();
+        public void mergeRepositories(Model model, boolean replace) {
+            if (model.getRepositories().isEmpty()) {
+                return;
+            }
+            // We need to interpolate the repositories before we can use them
+            Model interpolatedModel = interpolateModel(
+                    Model.newBuilder()
+                            .pomFile(model.getPomFile())
+                            .repositories(model.getRepositories())
+                            .build(),
+                    request,
+                    this);
+            List<RemoteRepository> repos = interpolatedModel.getRepositories().stream()
+                    .map(session::createRemoteRepository)
+                    .toList();
             if (replace) {
                 Set<String> ids = repos.stream().map(RemoteRepository::getId).collect(Collectors.toSet());
                 repositories = repositories.stream()
@@ -1016,7 +1027,7 @@ Model resolveAndReadParentExternally(Model childModel, DefaultProfileActivationC
             // add repositories specified by the current model so that we can resolve the parent
             if (!childModel.getRepositories().isEmpty()) {
                 var previousRepositories = repositories;
-                mergeRepositories(childModel.getRepositories(), false);
+                mergeRepositories(childModel, false);
                 if (!Objects.equals(previousRepositories, repositories)) {
                     if (logger.isDebugEnabled()) {
                         logger.debug("Merging repositories from " + childModel.getId() + "\n"
@@ -1196,7 +1207,7 @@ private Model readEffectiveModel() throws ModelBuilderException {
             if (!resultModel.getRepositories().isEmpty()) {
                 List<String> oldRepos =
                         repositories.stream().map(Object::toString).toList();
-                mergeRepositories(resultModel.getRepositories(), true);
+                mergeRepositories(resultModel, true);
                 List<String> newRepos =
                         repositories.stream().map(Object::toString).toList();
                 if (!Objects.equals(oldRepos, newRepos)) {
diff --git a/impl/maven-impl/src/test/java/org/apache/maven/impl/model/DefaultModelBuilderTest.java b/impl/maven-impl/src/test/java/org/apache/maven/impl/model/DefaultModelBuilderTest.java
index c0a04a92dfc3..2b012185c4bf 100644
--- a/impl/maven-impl/src/test/java/org/apache/maven/impl/model/DefaultModelBuilderTest.java
+++ b/impl/maven-impl/src/test/java/org/apache/maven/impl/model/DefaultModelBuilderTest.java
@@ -18,10 +18,17 @@
  */
 package org.apache.maven.impl.model;
 
+import java.lang.reflect.Field;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
 
+import org.apache.maven.api.RemoteRepository;
 import org.apache.maven.api.Session;
+import org.apache.maven.api.model.Model;
+import org.apache.maven.api.model.Repository;
 import org.apache.maven.api.services.ModelBuilder;
 import org.apache.maven.api.services.ModelBuilderRequest;
 import org.apache.maven.api.services.ModelBuilderResult;
@@ -60,6 +67,53 @@ public void testPropertiesAndProfiles() {
         assertEquals("21", result.getEffectiveModel().getProperties().get("maven.compiler.release"));
     }
 
+    @Test
+    public void testMergeRepositories() throws Exception {
+        // this is here only to trigger mainSession creation; unrelated
+        ModelBuilderRequest request = ModelBuilderRequest.builder()
+                .session(session)
+                .userProperties(Map.of("firstParentRepo", "https://some.repo"))
+                .requestType(ModelBuilderRequest.RequestType.BUILD_PROJECT)
+                .source(Sources.buildSource(getPom("props-and-profiles")))
+                .build();
+        ModelBuilder.ModelBuilderSession session = builder.newSession();
+        session.build(request); // ignored result value; just to trigger mainSession creation
+
+        Field mainSessionField = DefaultModelBuilder.ModelBuilderSessionImpl.class.getDeclaredField("mainSession");
+        mainSessionField.setAccessible(true);
+        DefaultModelBuilder.ModelBuilderSessionState state =
+                (DefaultModelBuilder.ModelBuilderSessionState) mainSessionField.get(session);
+        Field repositoriesField = DefaultModelBuilder.ModelBuilderSessionState.class.getDeclaredField("repositories");
+        repositoriesField.setAccessible(true);
+
+        List<RemoteRepository> repositories;
+        // before merge
+        repositories = (List<RemoteRepository>) repositoriesField.get(state);
+        assertEquals(1, repositories.size()); // central
+
+        Model model = Model.newBuilder()
+                .repositories(Arrays.asList(
+                        Repository.newBuilder()
+                                .id("first")
+                                .url("${firstParentRepo}")
+                                .build(),
+                        Repository.newBuilder()
+                                .id("second")
+                                .url("${secondParentRepo}")
+                                .build()))
+                .build();
+        state.mergeRepositories(model, false);
+
+        // after merge
+        repositories = (List<RemoteRepository>) repositoriesField.get(state);
+        assertEquals(3, repositories.size());
+        assertEquals("first", repositories.get(0).getId());
+        assertEquals("https://some.repo", repositories.get(0).getUrl()); // interpolated
+        assertEquals("second", repositories.get(1).getId());
+        assertEquals("${secondParentRepo}", repositories.get(1).getUrl()); // un-interpolated (no source)
+        assertEquals("central", repositories.get(2).getId()); // default
+    }
+
     private Path getPom(String name) {
         return Paths.get("src/test/resources/poms/factory/" + name + ".xml").toAbsolutePath();
     }