diff --git a/include/nlohmann/detail/conversions/from_json.hpp b/include/nlohmann/detail/conversions/from_json.hpp
index c6299aa0b..f7c972d5a 100644
--- a/include/nlohmann/detail/conversions/from_json.hpp
+++ b/include/nlohmann/detail/conversions/from_json.hpp
@@ -20,6 +20,14 @@
 #include <utility> // pair, declval
 #include <valarray> // valarray
 
+#ifdef JSON_HAS_CPP_17
+    #if __has_include(<optional>)
+        #include <optional>
+    #elif __has_include(<experimental/optional>)
+        #include <experimental/optional>
+    #endif
+#endif
+
 #include <nlohmann/detail/exceptions.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/cpp_future.hpp>
@@ -43,6 +51,21 @@ inline void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
     n = nullptr;
 }
 
+#ifdef JSON_HAS_CPP_17
+template<typename BasicJsonType, typename T>
+void from_json(const BasicJsonType& j, std::optional<T>& opt)
+{
+    if (j.is_null())
+    {
+        opt = std::nullopt;
+    }
+    else
+    {
+        opt = j.template get<T>();
+    }
+}
+#endif
+
 // overloads for basic_json template parameters
 template < typename BasicJsonType, typename ArithmeticType,
            enable_if_t < std::is_arithmetic<ArithmeticType>::value&&
diff --git a/include/nlohmann/detail/conversions/to_json.hpp b/include/nlohmann/detail/conversions/to_json.hpp
index b33d726b4..c14a1eb5e 100644
--- a/include/nlohmann/detail/conversions/to_json.hpp
+++ b/include/nlohmann/detail/conversions/to_json.hpp
@@ -24,6 +24,14 @@
 #include <nlohmann/detail/meta/type_traits.hpp>
 #include <nlohmann/detail/value_t.hpp>
 
+#ifdef JSON_HAS_CPP_17
+    #if __has_include(<optional>)
+        #include <optional>
+    #elif __has_include(<experimental/optional>)
+        #include <experimental/optional>
+    #endif
+#endif
+
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
 {
@@ -260,6 +268,22 @@ struct external_constructor<value_t::object>
 // to_json //
 /////////////
 
+#ifdef JSON_HAS_CPP_17
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_constructible<BasicJsonType, T>::value, int> = 0>
+void to_json(BasicJsonType& j, const std::optional<T>& opt)
+{
+    if (opt.has_value())
+    {
+        j = *opt;
+    }
+    else
+    {
+        j = nullptr;
+    }
+}
+#endif
+
 template<typename BasicJsonType, typename T,
          enable_if_t<std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
 inline void to_json(BasicJsonType& j, T b) noexcept
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 2448bf22d..4dfaa2bcc 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -169,6 +169,14 @@
 #include <utility> // pair, declval
 #include <valarray> // valarray
 
+#ifdef JSON_HAS_CPP_17
+    #if __has_include(<optional>)
+        #include <optional>
+    #elif __has_include(<experimental/optional>)
+        #include <experimental/optional>
+    #endif
+#endif
+
 // #include <nlohmann/detail/exceptions.hpp>
 //     __ _____ _____ _____
 //  __|  |   __|     |   | |  JSON for Modern C++
@@ -4603,6 +4611,21 @@ inline void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
     n = nullptr;
 }
 
+#ifdef JSON_HAS_CPP_17
+template<typename BasicJsonType, typename T>
+void from_json(const BasicJsonType& j, std::optional<T>& opt)
+{
+    if (j.is_null())
+    {
+        opt = std::nullopt;
+    }
+    else
+    {
+        opt = j.template get<T>();
+    }
+}
+#endif
+
 // overloads for basic_json template parameters
 template < typename BasicJsonType, typename ArithmeticType,
            enable_if_t < std::is_arithmetic<ArithmeticType>::value&&
@@ -5334,6 +5357,14 @@ class tuple_element<N, ::nlohmann::detail::iteration_proxy_value<IteratorType >>
 // #include <nlohmann/detail/value_t.hpp>
 
 
+#ifdef JSON_HAS_CPP_17
+    #if __has_include(<optional>)
+        #include <optional>
+    #elif __has_include(<experimental/optional>)
+        #include <experimental/optional>
+    #endif
+#endif
+
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
 {
@@ -5570,6 +5601,22 @@ struct external_constructor<value_t::object>
 // to_json //
 /////////////
 
+#ifdef JSON_HAS_CPP_17
+template<typename BasicJsonType, typename T,
+         enable_if_t<std::is_constructible<BasicJsonType, T>::value, int> = 0>
+void to_json(BasicJsonType& j, const std::optional<T>& opt)
+{
+    if (opt.has_value())
+    {
+        j = *opt;
+    }
+    else
+    {
+        j = nullptr;
+    }
+}
+#endif
+
 template<typename BasicJsonType, typename T,
          enable_if_t<std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0>
 inline void to_json(BasicJsonType& j, T b) noexcept
diff --git a/tests/src/unit-conversions.cpp b/tests/src/unit-conversions.cpp
index 9c6431238..49b6ccc41 100644
--- a/tests/src/unit-conversions.cpp
+++ b/tests/src/unit-conversions.cpp
@@ -32,6 +32,14 @@ using nlohmann::json;
 DOCTEST_CLANG_SUPPRESS_WARNING_PUSH
 DOCTEST_CLANG_SUPPRESS_WARNING("-Wexit-time-destructors")
 
+#ifdef JSON_HAS_CPP_17
+    #if __has_include(<optional>)
+        #include <optional>
+    #elif __has_include(<experimental/optional>)
+        #include <experimental/optional>
+    #endif
+#endif
+
 TEST_CASE("value conversion")
 {
     SECTION("get an object (explicit)")
@@ -1569,4 +1577,63 @@ TEST_CASE("JSON to enum mapping")
     }
 }
 
+#ifdef JSON_HAS_CPP_17
+TEST_CASE("std::optional")
+{
+    SECTION("null")
+    {
+        json j_null;
+        std::optional<std::string> opt_null;
+
+        CHECK(json(opt_null) == j_null);
+        CHECK(std::optional<std::string>(j_null) == std::nullopt);
+    }
+
+    SECTION("string")
+    {
+        json j_string = "string";
+        std::optional<std::string> opt_string = "string";
+
+        CHECK(json(opt_string) == j_string);
+        CHECK(std::optional<std::string>(j_string) == opt_string);
+    }
+
+    SECTION("bool")
+    {
+        json j_bool = true;
+        std::optional<bool> opt_bool = true;
+
+        CHECK(json(opt_bool) == j_bool);
+        CHECK(std::optional<bool>(j_bool) == opt_bool);
+    }
+
+    SECTION("number")
+    {
+        json j_number = 1;
+        std::optional<int> opt_int = 1;
+
+        CHECK(json(opt_int) == j_number);
+        CHECK(std::optional<int>(j_number) == opt_int);
+    }
+
+    SECTION("array")
+    {
+        json j_array = {1, 2, nullptr};
+        std::vector<std::optional<int>> opt_array = {{1, 2, std::nullopt}};
+
+        CHECK(json(opt_array) == j_array);
+        CHECK(std::vector<std::optional<int>>(j_array) == opt_array);
+    }
+
+    SECTION("object")
+    {
+        json j_object = {{"one", 1}, {"two", 2}, {"zero", nullptr}};
+        std::map<std::string, std::optional<int>> opt_object {{"one", 1}, {"two", 2}, {"zero", std::nullopt}};
+
+        CHECK(json(opt_object) == j_object);
+        CHECK(std::map<std::string, std::optional<int>>(j_object) == opt_object);
+    }
+}
+#endif
+
 DOCTEST_CLANG_SUPPRESS_WARNING_POP