diff --git a/devel/nlohmann-json/Makefile b/devel/nlohmann-json/Makefile
index f65d281ea8be..5e716f968368 100644
--- a/devel/nlohmann-json/Makefile
+++ b/devel/nlohmann-json/Makefile
@@ -1,25 +1,27 @@
 PORTNAME=	json
 DISTVERSIONPREFIX=	v
-DISTVERSION=	3.11.3
+DISTVERSION=	3.12.0
 CATEGORIES=	devel
 PKGNAMEPREFIX=	nlohmann-
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	JSON library for Modern C++
 WWW=		https://nlohmann.github.io/json/
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE.MIT
 
 USES=		cmake:testing compiler:c++11-lib
 USE_GITHUB=	yes
 GH_ACCOUNT=	nlohmann
 
 NO_BUILD=	yes
 NO_ARCH=	yes
 
 CMAKE_ON=	JSON_MultipleHeaders
 CMAKE_OFF=	JSON_BuildTests
-CMAKE_TESTING_ON=	JSON_BuildTests # 2 tests are expected to fail, see https://github.com/nlohmann/json/issues/2951
+CMAKE_TESTING_ON=	JSON_BuildTests
+
+# tests as of 3.12.0: 96% tests passed, 4 tests failed out of 101 (4 cmake_fetch_content* tests fail, https://github.com/nlohmann/json/issues/2951)
 
 .include <bsd.port.mk>
diff --git a/devel/nlohmann-json/distinfo b/devel/nlohmann-json/distinfo
index 071fa96fa526..aebebac1b464 100644
--- a/devel/nlohmann-json/distinfo
+++ b/devel/nlohmann-json/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1701242299
-SHA256 (nlohmann-json-v3.11.3_GH0.tar.gz) = 0d8ef5af7f9794e3263480193c491549b2ba6cc74bb018906202ada498a79406
-SIZE (nlohmann-json-v3.11.3_GH0.tar.gz) = 8053705
+TIMESTAMP = 1744489818
+SHA256 (nlohmann-json-v3.12.0_GH0.tar.gz) = 4b92eb0c06d10683f7447ce9406cb97cd4b453be18d7279320f7b2f025c10187
+SIZE (nlohmann-json-v3.12.0_GH0.tar.gz) = 9678593
diff --git a/devel/nlohmann-json/pkg-plist b/devel/nlohmann-json/pkg-plist
index 2cee127add49..ac5db286846b 100644
--- a/devel/nlohmann-json/pkg-plist
+++ b/devel/nlohmann-json/pkg-plist
@@ -1,49 +1,50 @@
 include/nlohmann/adl_serializer.hpp
 include/nlohmann/byte_container_with_subtype.hpp
 include/nlohmann/detail/abi_macros.hpp
 include/nlohmann/detail/conversions/from_json.hpp
 include/nlohmann/detail/conversions/to_chars.hpp
 include/nlohmann/detail/conversions/to_json.hpp
 include/nlohmann/detail/exceptions.hpp
 include/nlohmann/detail/hash.hpp
 include/nlohmann/detail/input/binary_reader.hpp
 include/nlohmann/detail/input/input_adapters.hpp
 include/nlohmann/detail/input/json_sax.hpp
 include/nlohmann/detail/input/lexer.hpp
 include/nlohmann/detail/input/parser.hpp
 include/nlohmann/detail/input/position_t.hpp
 include/nlohmann/detail/iterators/internal_iterator.hpp
 include/nlohmann/detail/iterators/iter_impl.hpp
 include/nlohmann/detail/iterators/iteration_proxy.hpp
 include/nlohmann/detail/iterators/iterator_traits.hpp
 include/nlohmann/detail/iterators/json_reverse_iterator.hpp
 include/nlohmann/detail/iterators/primitive_iterator.hpp
 include/nlohmann/detail/json_custom_base_class.hpp
 include/nlohmann/detail/json_pointer.hpp
 include/nlohmann/detail/json_ref.hpp
 include/nlohmann/detail/macro_scope.hpp
 include/nlohmann/detail/macro_unscope.hpp
 include/nlohmann/detail/meta/call_std/begin.hpp
 include/nlohmann/detail/meta/call_std/end.hpp
 include/nlohmann/detail/meta/cpp_future.hpp
 include/nlohmann/detail/meta/detected.hpp
 include/nlohmann/detail/meta/identity_tag.hpp
 include/nlohmann/detail/meta/is_sax.hpp
 include/nlohmann/detail/meta/std_fs.hpp
 include/nlohmann/detail/meta/type_traits.hpp
 include/nlohmann/detail/meta/void_t.hpp
 include/nlohmann/detail/output/binary_writer.hpp
 include/nlohmann/detail/output/output_adapters.hpp
 include/nlohmann/detail/output/serializer.hpp
 include/nlohmann/detail/string_concat.hpp
 include/nlohmann/detail/string_escape.hpp
+include/nlohmann/detail/string_utils.hpp
 include/nlohmann/detail/value_t.hpp
 include/nlohmann/json.hpp
 include/nlohmann/json_fwd.hpp
 include/nlohmann/ordered_map.hpp
 include/nlohmann/thirdparty/hedley/hedley.hpp
 include/nlohmann/thirdparty/hedley/hedley_undef.hpp
 share/cmake/nlohmann_json/nlohmann_jsonConfig.cmake
 share/cmake/nlohmann_json/nlohmann_jsonConfigVersion.cmake
 share/cmake/nlohmann_json/nlohmann_jsonTargets.cmake
 share/pkgconfig/nlohmann_json.pc