diff --git a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Parser.cs b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Parser.cs
index 4339851dce17cb..97d0c0849909cf 100644
--- a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Parser.cs
+++ b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Parser.cs
@@ -1514,6 +1514,11 @@ private void ProcessMember(
                         continue;
                     }
 
+                    if (property.DefaultIgnoreCondition == JsonIgnoreCondition.Always && !property.IsRequired)
+                    {
+                        continue;
+                    }
+
                     if ((property.IsRequired && !constructorSetsRequiredMembers) || property.IsInitOnlySetter)
                     {
                         if (!(memberInitializerNames ??= new()).Add(property.MemberName))
diff --git a/src/libraries/System.Text.Json/tests/Common/PropertyVisibilityTests.InitOnly.cs b/src/libraries/System.Text.Json/tests/Common/PropertyVisibilityTests.InitOnly.cs
index a0547a4bf55ff9..285b199ab71631 100644
--- a/src/libraries/System.Text.Json/tests/Common/PropertyVisibilityTests.InitOnly.cs
+++ b/src/libraries/System.Text.Json/tests/Common/PropertyVisibilityTests.InitOnly.cs
@@ -64,6 +64,29 @@ public virtual async Task NonPublicInitOnlySetter_With_JsonInclude(Type type)
             Assert.Equal(@"{""MyInt"":1}", await Serializer.SerializeWrapper(obj));
         }
 
+        [Theory]
+        [InlineData(typeof(Class_WithIgnoredInitOnlyProperty_WithDefaultValue))]
+        [InlineData(typeof(Record_WithIgnoredPropertyInCtor_WithDefaultValue))]
+        public async Task InitOnlySetter_With_JsonIgnoreAlways_AndWith_DefaultValue(Type type)
+        {
+            object obj = await Serializer.DeserializeWrapper(@"{""MyInt"":1}", type);
+            Assert.Equal(42, (int)type.GetProperty("MyInt").GetValue(obj));
+        }
+
+        [Fact]
+        public async Task JsonIgnoreOnInitOnlyProperty()
+        {
+            // Regression test for https://github.com/dotnet/runtime/issues/101877
+
+            RecordWithIgnoredNestedInitOnlyProperty.InnerRecord inner = new(42, "Baz");
+            RecordWithIgnoredNestedInitOnlyProperty value = new RecordWithIgnoredNestedInitOnlyProperty(inner);
+            string json = await Serializer.SerializeWrapper(value);
+            Assert.Equal("""{"foo":42}""", json);
+
+            RecordWithIgnoredNestedInitOnlyProperty? deserializedValue = await Serializer.DeserializeWrapper<RecordWithIgnoredNestedInitOnlyProperty>(json);
+            Assert.Equal(value, deserializedValue);
+        }
+
         [Fact]
         public async Task NullableStructWithInitOnlyProperty()
         {
@@ -132,5 +155,28 @@ public class Class_PropertyWith_ProtectedInitOnlySetter_WithAttribute
             [JsonInclude]
             public int MyInt { get; protected init; }
         }
+
+        public class Class_WithIgnoredInitOnlyProperty_WithDefaultValue
+        {
+            [JsonIgnore(Condition = JsonIgnoreCondition.Always)]
+            public int MyInt { get; init; } = 42;
+        }
+
+        public record Record_WithIgnoredPropertyInCtor_WithDefaultValue(
+            [property: JsonIgnore] int MyInt = 42);
+
+        public record RecordWithIgnoredNestedInitOnlyProperty(
+            [property: JsonIgnore] RecordWithIgnoredNestedInitOnlyProperty.InnerRecord Other)
+        {
+            [JsonConstructor]
+            public RecordWithIgnoredNestedInitOnlyProperty(int foo)
+                : this(new InnerRecord(foo, "Baz"))
+            {
+            }
+
+            [JsonPropertyName("foo")] public int Foo => Other.Foo;
+
+            public record InnerRecord(int Foo, string Bar);
+        }
     }
 }
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/PropertyVisibilityTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/PropertyVisibilityTests.cs
index 21f220509ad360..bce43700c2548d 100644
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/PropertyVisibilityTests.cs
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/PropertyVisibilityTests.cs
@@ -198,6 +198,9 @@ public override async Task ClassWithIgnoredAndPrivateMembers_DoesNotIncludeIgnor
         [JsonSerializable(typeof(ClassWithStructProperty_IgnoreConditionWhenWritingDefault))]
         [JsonSerializable(typeof(ClassWithMissingObjectProperty))]
         [JsonSerializable(typeof(ClassWithInitOnlyProperty))]
+        [JsonSerializable(typeof(Class_WithIgnoredInitOnlyProperty_WithDefaultValue))]
+        [JsonSerializable(typeof(Record_WithIgnoredPropertyInCtor_WithDefaultValue))]
+        [JsonSerializable(typeof(RecordWithIgnoredNestedInitOnlyProperty))]
         [JsonSerializable(typeof(StructWithInitOnlyProperty))]
         [JsonSerializable(typeof(StructWithInitOnlyProperty?))]
         [JsonSerializable(typeof(ClassWithCustomNamedInitOnlyProperty))]
@@ -473,6 +476,9 @@ partial class DefaultContextWithGlobalIgnoreSetting : JsonSerializerContext;
         [JsonSerializable(typeof(ClassWithStructProperty_IgnoreConditionWhenWritingDefault))]
         [JsonSerializable(typeof(ClassWithMissingObjectProperty))]
         [JsonSerializable(typeof(ClassWithInitOnlyProperty))]
+        [JsonSerializable(typeof(Class_WithIgnoredInitOnlyProperty_WithDefaultValue))]
+        [JsonSerializable(typeof(Record_WithIgnoredPropertyInCtor_WithDefaultValue))]
+        [JsonSerializable(typeof(RecordWithIgnoredNestedInitOnlyProperty))]
         [JsonSerializable(typeof(StructWithInitOnlyProperty))]
         [JsonSerializable(typeof(StructWithInitOnlyProperty?))]
         [JsonSerializable(typeof(ClassWithCustomNamedInitOnlyProperty))]