diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 86e85fc19..78b55c295 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -38,6 +38,7 @@ It has long been unused by Sirius Web itself (since the transition to MUI).
 - https://github.com/eclipse-syson/syson/issues/2331[#2331] [diagrams] Fix the broken `New Interface` tool icon.
 - https://github.com/eclipse-syson/syson/issues/2320[#2320] [diagrams] Add an explicit warning message when user tries to reconnect one Actor's edge to another Actor.
 - https://github.com/eclipse-syson/syson/issues/2329[#2329] [import] Fix importing requirement (and sub-requirement) a text.
+- https://github.com/eclipse-syson/syson/issues/2336[#2336] [details] Fix _Edit expression_ modal when the selected element is a `FeatureValue`
 
 === Improvements
 
diff --git a/backend/application/syson-application/src/test/java/org/eclipse/syson/application/controllers/expressions/ExpressionsControllersIntegrationTests.java b/backend/application/syson-application/src/test/java/org/eclipse/syson/application/controllers/expressions/ExpressionsControllersIntegrationTests.java
index f511fb788..22d39e931 100644
--- a/backend/application/syson-application/src/test/java/org/eclipse/syson/application/controllers/expressions/ExpressionsControllersIntegrationTests.java
+++ b/backend/application/syson-application/src/test/java/org/eclipse/syson/application/controllers/expressions/ExpressionsControllersIntegrationTests.java
@@ -324,6 +324,51 @@ public void textEditAttributeExpression() {
                 .verify(Duration.ofSeconds(10));
     }
 
+    @DisplayName("GIVEN a SysML the FeatueValue of an attribute that has an existing expression, WHEN editing the expression to a new one THEN the attribute's expression is replaced")
+    @GivenSysONServer({ ExpressionSamplesProjectData.SCRIPT_PATH })
+    @Test
+    public void textEditFeatureValueExpression() {
+        String editingContextId = ExpressionSamplesProjectData.EDITING_CONTEXT_ID;
+
+        List<String> defaultFilters = this.explorerDefaultFiltersSearchService.findTreeDefaultFilterIds(editingContextId, this.sysONExplorerTreeDescriptionId);
+        var explorerRepresentationId = this.representationIdBuilder.buildExplorerRepresentationId(this.sysONExplorerTreeDescriptionId, List.of(), defaultFilters);
+        var explorerInput = new ExplorerEventInput(UUID.randomUUID(), editingContextId, explorerRepresentationId);
+        var flux = this.explorerEventSubscriptionRunner.run(explorerInput).flux();
+
+        var treeId = new AtomicReference<String>();
+        Consumer<Object> initialTreeContentConsumer = assertRefreshedTreeThat(tree -> {
+            assertThat(tree).isNotNull();
+            treeId.set(tree.getId());
+        });
+
+        var existingExpressionId = new AtomicReference<String>();
+
+        Runnable checkInitialExpression = this.checkElementHasExpression(editingContextId,
+                ExpressionSamplesProjectData.SemanticIds.TANK_MAX_VOLUME_ATTRIBUTE_FEATURE_VALUE_ID, FeatureValue.class, existingExpressionId,
+                "100.0 * minVolume");
+
+        Runnable editExpressionOnMaxVolumeAttribute = this.editExpression(editingContextId, existingExpressionId::get, "50 * minVolume");
+
+        Consumer<Object> treeRefreshed = assertRefreshedTreeThat(tree -> {
+            assertThat(tree).isNotNull();
+            assertThat(tree.getId()).isEqualTo(treeId.get());
+        });
+
+        Runnable checkExpressionUpdated = this.checkElementHasExpression(editingContextId, ExpressionSamplesProjectData.SemanticIds.TANK_MAX_VOLUME_ATTRIBUTE_FEATURE_VALUE_ID,
+                FeatureValue.class,
+                existingExpressionId,
+                "50 * minVolume");
+
+        StepVerifier.create(flux)
+                .consumeNextWith(initialTreeContentConsumer)
+                .then(checkInitialExpression)
+                .then(editExpressionOnMaxVolumeAttribute)
+                .consumeNextWith(treeRefreshed)
+                .then(checkExpressionUpdated)
+                .thenCancel()
+                .verify(Duration.ofSeconds(10));
+    }
+
     @DisplayName("GIVEN a SysML attribute with a value expression, WHEN editing it with feature value properties THEN the flags are updated together with the expression")
     @GivenSysONServer({ ExpressionSamplesProjectData.SCRIPT_PATH })
     @Test
diff --git a/backend/application/syson-application/src/test/java/org/eclipse/syson/application/data/ExpressionSamplesProjectData.java b/backend/application/syson-application/src/test/java/org/eclipse/syson/application/data/ExpressionSamplesProjectData.java
index ec9d8c94e..547843014 100644
--- a/backend/application/syson-application/src/test/java/org/eclipse/syson/application/data/ExpressionSamplesProjectData.java
+++ b/backend/application/syson-application/src/test/java/org/eclipse/syson/application/data/ExpressionSamplesProjectData.java
@@ -38,6 +38,8 @@ public static final class SemanticIds {
 
         public static final String TANK_MAX_VOLUME_ATTRIBUTE_ID = "d9926727-7378-4177-a940-2fb6c1c89dce";
 
+        public static final String TANK_MAX_VOLUME_ATTRIBUTE_FEATURE_VALUE_ID = "8f9592ef-9513-4025-ab13-e7d7f822f7d8";
+
         public static final String TANK_MAX_VOLUME_ATTRIBUTE_VALUE_ID = "a9216e54-f44c-4b1f-b262-13650324d325";
 
         public static final String TANK_PRESSURE_LIMIT_CONSTRAINT_ID = "7d42ee06-3c27-4eaa-9438-344fc789906a";
diff --git a/backend/application/syson-sysml-import/src/main/java/org/eclipse/syson/sysml/services/EditExpressionEventHandler.java b/backend/application/syson-sysml-import/src/main/java/org/eclipse/syson/sysml/services/EditExpressionEventHandler.java
index 095e315e4..d2b38599d 100644
--- a/backend/application/syson-sysml-import/src/main/java/org/eclipse/syson/sysml/services/EditExpressionEventHandler.java
+++ b/backend/application/syson-sysml-import/src/main/java/org/eclipse/syson/sysml/services/EditExpressionEventHandler.java
@@ -29,6 +29,7 @@
 import org.eclipse.sirius.components.emf.services.api.IEMFEditingContext;
 import org.eclipse.syson.sysml.Element;
 import org.eclipse.syson.sysml.Expression;
+import org.eclipse.syson.sysml.Relationship;
 import org.eclipse.syson.sysml.dto.EditExpressionInput;
 import org.eclipse.syson.sysml.dto.EditExpressionSuccessPayload;
 import org.eclipse.syson.sysml.metamodel.services.MetamodelQueryElementService;
@@ -87,7 +88,11 @@ public void handle(Sinks.One<IPayload> payloadSink, Sinks.Many<ChangeDescription
             var optionalExpression = this.getExpression(emfEditingContext, editExpressionInput.elementId());
 
             if (optionalParent.isPresent() && optionalExpression.isPresent()) {
-                var result = this.expressionEditor.editExpression(emfEditingContext, optionalParent.get(), optionalExpression.get(), editExpressionInput.newExpressionText(),
+                var parentElement = optionalParent.get();
+                if (parentElement instanceof Relationship relationship) {
+                    parentElement = relationship.getOwningRelatedElement();
+                }
+                var result = this.expressionEditor.editExpression(emfEditingContext, parentElement, optionalExpression.get(), editExpressionInput.newExpressionText(),
                         editExpressionInput.properties());
                 if (result.createdExpression() != null) {
                     var newExpression = result.createdExpression();
diff --git a/backend/services/syson-sysml-metamodel-services/src/main/java/org/eclipse/syson/sysml/metamodel/services/MetamodelQueryElementService.java b/backend/services/syson-sysml-metamodel-services/src/main/java/org/eclipse/syson/sysml/metamodel/services/MetamodelQueryElementService.java
index a325b8071..a97b456ae 100644
--- a/backend/services/syson-sysml-metamodel-services/src/main/java/org/eclipse/syson/sysml/metamodel/services/MetamodelQueryElementService.java
+++ b/backend/services/syson-sysml-metamodel-services/src/main/java/org/eclipse/syson/sysml/metamodel/services/MetamodelQueryElementService.java
@@ -18,6 +18,7 @@
 import java.util.Optional;
 import java.util.function.Predicate;
 
+import org.eclipse.emf.common.util.EList;
 import org.eclipse.syson.sysml.ActorMembership;
 import org.eclipse.syson.sysml.BooleanExpression;
 import org.eclipse.syson.sysml.ConcernUsage;
@@ -32,6 +33,7 @@
 import org.eclipse.syson.sysml.OwningMembership;
 import org.eclipse.syson.sysml.PartUsage;
 import org.eclipse.syson.sysml.ReferenceUsage;
+import org.eclipse.syson.sysml.Relationship;
 import org.eclipse.syson.sysml.RequirementConstraintMembership;
 import org.eclipse.syson.sysml.ResultExpressionMembership;
 import org.eclipse.syson.sysml.StakeholderMembership;
@@ -183,7 +185,13 @@ public Optional<Expression> findSingleExpressionDefinition(Element element) {
         if (this.isExpressionDefinition(element)) {
             result = Optional.of((Expression) element);
         } else {
-            var ownedExpressions = element.getOwnedElement().stream().filter(child -> this.isExpressionDefinition(child)).toList();
+            EList<Element> ownedElements;
+            if (element instanceof Relationship relationship) {
+                ownedElements = relationship.getOwnedRelatedElement();
+            } else {
+                ownedElements = element.getOwnedElement();
+            }
+            var ownedExpressions = ownedElements.stream().filter(child -> this.isExpressionDefinition(child)).toList();
             if (ownedExpressions.size() == 1) {
                 result = Optional.of((Expression) ownedExpressions.get(0));
             }