diff --git a/core/src/cubos/core/ecs/world.cpp b/core/src/cubos/core/ecs/world.cpp
index 6100ebea5..3ca2e074f 100644
--- a/core/src/cubos/core/ecs/world.cpp
+++ b/core/src/cubos/core/ecs/world.cpp
@@ -256,7 +256,34 @@ auto World::Components::add(const reflection::Type& type, void* value) -> Compon
     newTable.column(columnId).pushMove(value);
 
     // For each sparse relation table the entity is on, move its relations to the new corresponding one.
-    // TODO
+    for (const auto& [_, index] : mWorld.mTables.sparseRelation())
+    {
+        // For each table where the entity's archetype is the 'from' archetype.
+        if (index.from().contains(oldArchetype))
+        {
+            for (const auto& oldTableId : index.from().at(oldArchetype))
+            {
+                // Move all occurrences of the entity in the 'from' column to the new table.
+                auto newTableId = oldTableId;
+                newTableId.from = newArchetype;
+                auto& newTable = mWorld.mTables.sparseRelation().create(newTableId, mWorld.mTypes);
+                mWorld.mTables.sparseRelation().at(oldTableId).moveFrom(mEntity.index, newTable);
+            }
+        }
+
+        // For each table where the entity's archetype is the 'to' archetype.
+        if (index.to().contains(oldArchetype))
+        {
+            for (const auto& oldTableId : index.to().at(oldArchetype))
+            {
+                // Move all occurrences of the entity in the 'to' column to the new table.
+                auto newTableId = oldTableId;
+                newTableId.to = newArchetype;
+                auto& newTable = mWorld.mTables.sparseRelation().create(newTableId, mWorld.mTypes);
+                mWorld.mTables.sparseRelation().at(oldTableId).moveTo(mEntity.index, newTable);
+            }
+        }
+    }
 
     CUBOS_DEBUG("Added component {} to entity {}", type.name(), mEntity, mEntity);
     return *this;
@@ -288,7 +315,34 @@ auto World::Components::remove(const reflection::Type& type) -> Components&
     oldTable.swapMove(mEntity.index, newTable);
 
     // For each sparse relation table the entity is on, move its relations to the new corresponding one.
-    // TODO
+    for (const auto& [_, index] : mWorld.mTables.sparseRelation())
+    {
+        // For each table where the entity's archetype is the 'from' archetype.
+        if (index.from().contains(oldArchetype))
+        {
+            for (const auto& oldTableId : index.from().at(oldArchetype))
+            {
+                // Move all occurrences of the entity in the 'from' column to the new table.
+                auto newTableId = oldTableId;
+                newTableId.from = newArchetype;
+                auto& newTable = mWorld.mTables.sparseRelation().create(newTableId, mWorld.mTypes);
+                mWorld.mTables.sparseRelation().at(oldTableId).moveFrom(mEntity.index, newTable);
+            }
+        }
+
+        // For each table where the entity's archetype is the 'to' archetype.
+        if (index.to().contains(oldArchetype))
+        {
+            for (const auto& oldTableId : index.to().at(oldArchetype))
+            {
+                // Move all occurrences of the entity in the 'to' column to the new table.
+                auto newTableId = oldTableId;
+                newTableId.to = newArchetype;
+                auto& newTable = mWorld.mTables.sparseRelation().create(newTableId, mWorld.mTypes);
+                mWorld.mTables.sparseRelation().at(oldTableId).moveTo(mEntity.index, newTable);
+            }
+        }
+    }
 
     CUBOS_DEBUG("Removed component {} from entity {}", type.name(), mEntity);
     return *this;
diff --git a/core/tests/ecs/world.cpp b/core/tests/ecs/world.cpp
index 60684f48f..410820635 100644
--- a/core/tests/ecs/world.cpp
+++ b/core/tests/ecs/world.cpp
@@ -209,4 +209,37 @@ TEST_CASE("ecs::World")
 
         CHECK(destroyed);
     }
+
+    SUBCASE("relations are moved correctly between archetypes")
+    {
+        bool destroyed = false;
+        auto foo = world.create();
+        auto bar = world.create();
+
+        // Add a relation between foo and bar.
+        REQUIRE_FALSE(world.related<DetectDestructorRelation>(foo, bar));
+        world.relate(foo, bar, DetectDestructorRelation{{&destroyed}});
+        REQUIRE(world.related<DetectDestructorRelation>(foo, bar));
+        REQUIRE_FALSE(destroyed);
+
+        // Change the archetype of foo. The entities should still be related.
+        world.components(foo).add(IntegerComponent{0});
+        REQUIRE(world.related<DetectDestructorRelation>(foo, bar));
+        REQUIRE_FALSE(destroyed);
+
+        // Change the archetype of bar. The entities should still be related.
+        world.components(bar).add(IntegerComponent{0});
+        REQUIRE(world.related<DetectDestructorRelation>(foo, bar));
+        REQUIRE_FALSE(destroyed);
+
+        // Change the archetypes once again.
+        world.components(foo).remove<IntegerComponent>();
+        world.components(bar).remove<IntegerComponent>();
+        REQUIRE(world.related<DetectDestructorRelation>(foo, bar));
+        REQUIRE_FALSE(destroyed);
+
+        // Destroy foo. The relation should be destroyed.
+        world.destroy(foo);
+        REQUIRE(destroyed);
+    }
 }