diff --git a/openai-java-core/src/main/kotlin/com/openai/core/ObjectMappers.kt b/openai-java-core/src/main/kotlin/com/openai/core/ObjectMappers.kt
index 7be25df3..24bec380 100644
--- a/openai-java-core/src/main/kotlin/com/openai/core/ObjectMappers.kt
+++ b/openai-java-core/src/main/kotlin/com/openai/core/ObjectMappers.kt
@@ -4,12 +4,16 @@ package com.openai.core
 
 import com.fasterxml.jackson.annotation.JsonInclude
 import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.core.JsonParseException
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.DeserializationContext
 import com.fasterxml.jackson.databind.DeserializationFeature
 import com.fasterxml.jackson.databind.MapperFeature
 import com.fasterxml.jackson.databind.SerializationFeature
 import com.fasterxml.jackson.databind.SerializerProvider
 import com.fasterxml.jackson.databind.cfg.CoercionAction
 import com.fasterxml.jackson.databind.cfg.CoercionInputShape
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer
 import com.fasterxml.jackson.databind.json.JsonMapper
 import com.fasterxml.jackson.databind.module.SimpleModule
 import com.fasterxml.jackson.databind.type.LogicalType
@@ -17,13 +21,23 @@ import com.fasterxml.jackson.datatype.jdk8.Jdk8Module
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
 import com.fasterxml.jackson.module.kotlin.kotlinModule
 import java.io.InputStream
+import java.time.DateTimeException
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.ZonedDateTime
+import java.time.format.DateTimeFormatter
+import java.time.temporal.ChronoField
 
 fun jsonMapper(): JsonMapper =
     JsonMapper.builder()
         .addModule(kotlinModule())
         .addModule(Jdk8Module())
         .addModule(JavaTimeModule())
-        .addModule(SimpleModule().addSerializer(InputStreamJsonSerializer))
+        .addModule(
+            SimpleModule()
+                .addSerializer(InputStreamSerializer)
+                .addDeserializer(LocalDateTime::class.java, LenientLocalDateTimeDeserializer())
+        )
         .withCoercionConfig(LogicalType.Boolean) {
             it.setCoercion(CoercionInputShape.Integer, CoercionAction.Fail)
                 .setCoercion(CoercionInputShape.Float, CoercionAction.Fail)
@@ -91,7 +105,10 @@ fun jsonMapper(): JsonMapper =
         .disable(MapperFeature.AUTO_DETECT_SETTERS)
         .build()
 
-private object InputStreamJsonSerializer : BaseSerializer<InputStream>(InputStream::class) {
+/** A serializer that serializes [InputStream] to bytes. */
+private object InputStreamSerializer : BaseSerializer<InputStream>(InputStream::class) {
+
+    private fun readResolve(): Any = InputStreamSerializer
 
     override fun serialize(
         value: InputStream?,
@@ -105,3 +122,46 @@ private object InputStreamJsonSerializer : BaseSerializer<InputStream>(InputStre
         }
     }
 }
+
+/**
+ * A deserializer that can deserialize [LocalDateTime] from datetimes, dates, and zoned datetimes.
+ */
+private class LenientLocalDateTimeDeserializer :
+    StdDeserializer<LocalDateTime>(LocalDateTime::class.java) {
+
+    companion object {
+
+        private val DATE_TIME_FORMATTERS =
+            listOf(
+                DateTimeFormatter.ISO_LOCAL_DATE_TIME,
+                DateTimeFormatter.ISO_LOCAL_DATE,
+                DateTimeFormatter.ISO_ZONED_DATE_TIME,
+            )
+    }
+
+    override fun logicalType(): LogicalType = LogicalType.DateTime
+
+    override fun deserialize(p: JsonParser, context: DeserializationContext?): LocalDateTime {
+        val exceptions = mutableListOf<Exception>()
+
+        for (formatter in DATE_TIME_FORMATTERS) {
+            try {
+                val temporal = formatter.parse(p.text)
+
+                return when {
+                    !temporal.isSupported(ChronoField.HOUR_OF_DAY) ->
+                        LocalDate.from(temporal).atStartOfDay()
+                    !temporal.isSupported(ChronoField.OFFSET_SECONDS) ->
+                        LocalDateTime.from(temporal)
+                    else -> ZonedDateTime.from(temporal).toLocalDateTime()
+                }
+            } catch (e: DateTimeException) {
+                exceptions.add(e)
+            }
+        }
+
+        throw JsonParseException(p, "Cannot parse `LocalDateTime` from value: ${p.text}").apply {
+            exceptions.forEach { addSuppressed(it) }
+        }
+    }
+}
diff --git a/openai-java-core/src/test/kotlin/com/openai/core/ObjectMappersTest.kt b/openai-java-core/src/test/kotlin/com/openai/core/ObjectMappersTest.kt
index 17fe45c3..2dbf1a4c 100644
--- a/openai-java-core/src/test/kotlin/com/openai/core/ObjectMappersTest.kt
+++ b/openai-java-core/src/test/kotlin/com/openai/core/ObjectMappersTest.kt
@@ -2,10 +2,15 @@ package com.openai.core
 
 import com.fasterxml.jackson.annotation.JsonProperty
 import com.fasterxml.jackson.databind.exc.MismatchedInputException
+import com.fasterxml.jackson.module.kotlin.readValue
+import java.time.LocalDateTime
 import kotlin.reflect.KClass
 import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.catchThrowable
 import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertDoesNotThrow
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.EnumSource
 import org.junitpioneer.jupiter.cartesian.CartesianTest
 
 internal class ObjectMappersTest {
@@ -78,4 +83,20 @@ internal class ObjectMappersTest {
             assertThat(e).isInstanceOf(MismatchedInputException::class.java)
         }
     }
+
+    enum class LenientLocalDateTimeTestCase(val string: String) {
+        DATE("1998-04-21"),
+        DATE_TIME("1998-04-21T04:00:00"),
+        ZONED_DATE_TIME_1("1998-04-21T04:00:00+03:00"),
+        ZONED_DATE_TIME_2("1998-04-21T04:00:00Z"),
+    }
+
+    @ParameterizedTest
+    @EnumSource
+    fun readLocalDateTime_lenient(testCase: LenientLocalDateTimeTestCase) {
+        val jsonMapper = jsonMapper()
+        val json = jsonMapper.writeValueAsString(testCase.string)
+
+        assertDoesNotThrow { jsonMapper().readValue<LocalDateTime>(json) }
+    }
 }