diff --git a/autobuild.xml b/autobuild.xml
index 5d3f1a881..880176e81 100644
--- a/autobuild.xml
+++ b/autobuild.xml
@@ -1933,38 +1933,6 @@
         <key>version</key>
         <string>7.11.1.297294</string>
       </map>
-      <key>modernjson</key>
-      <map>
-        <key>copyright</key>
-        <string>Copyright (c) 2013-2018 Niels Lohmann</string>
-        <key>description</key>
-        <string>JSON for Modern C++</string>
-        <key>license</key>
-        <string>MIT</string>
-        <key>license_file</key>
-        <string>LICENSES/modernjson.txt</string>
-        <key>name</key>
-        <string>modernjson</string>
-        <key>platforms</key>
-        <map>
-          <key>common</key>
-          <map>
-            <key>archive</key>
-            <map>
-              <key>hash</key>
-              <string>6f11eca7e2a6ca61f9217e949a64f026</string>
-              <key>hash_algorithm</key>
-              <string>md5</string>
-              <key>url</key>
-              <string>https://depot.alchemyviewer.org/pub/common/lib/modernjson-3.2.0-common-201809210551.tar.bz2</string>
-            </map>
-            <key>name</key>
-            <string>common</string>
-          </map>
-        </map>
-        <key>version</key>
-        <string>3.2.0</string>
-      </map>
       <key>nvapi</key>
       <map>
         <key>copyright</key>
diff --git a/indra/cmake/CMakeLists.txt b/indra/cmake/CMakeLists.txt
index 8202868a1..cfd982f96 100644
--- a/indra/cmake/CMakeLists.txt
+++ b/indra/cmake/CMakeLists.txt
@@ -50,7 +50,6 @@ set(cmake_SOURCE_FILES
     GooglePerfTools.cmake
     Hunspell.cmake
     JPEG.cmake
-    Json.cmake
     LLAddBuildTest.cmake
     LLAppearance.cmake
     LLAudio.cmake
diff --git a/indra/deps/CMakeLists.txt b/indra/deps/CMakeLists.txt
index fb2ed3050..af512a87b 100644
--- a/indra/deps/CMakeLists.txt
+++ b/indra/deps/CMakeLists.txt
@@ -15,6 +15,11 @@ FetchContent_Declare(
   GIT_REPOSITORY https://github.com/fmtlib/fmt.git
   GIT_TAG        6.1.2
   )
+FetchContent_Declare(
+  nlohmann_json
+  GIT_REPOSITORY https://github.com/nlohmann/json.git
+  GIT_TAG        v3.7.3
+  )
 FetchContent_Declare(
   absl
   GIT_REPOSITORY https://github.com/abseil/abseil-cpp.git
@@ -44,5 +49,14 @@ if(WINDOWS)
 FetchContent_MakeAvailable(fmt)
 endif()
 
+# Typically you don't care so much for a third party library's tests to be
+# run from your own project's code.
+set(JSON_BuildTests OFF CACHE INTERNAL "")
+
+# If you only include this third party in PRIVATE source files, you do not
+# need to install it when your main project gets installed.
+set(JSON_Install OFF CACHE INTERNAL "")
+FetchContent_MakeAvailable(nlohmann_json)
+
 unset(CMAKE_FOLDER)
 unset(CMAKE_POSITION_INDEPENDENT_CODE)
diff --git a/indra/llcommon/CMakeLists.txt b/indra/llcommon/CMakeLists.txt
index 9baf87d9d..1d9df704e 100644
--- a/indra/llcommon/CMakeLists.txt
+++ b/indra/llcommon/CMakeLists.txt
@@ -12,7 +12,6 @@ include(Linking)
 include(Boost)
 include(OpenSSL)
 include(LLSharedLibs)
-include(Json)
 include(Copy3rdPartyLibs)
 include(ZLIB)
 include(URIPARSER)
@@ -300,6 +299,7 @@ target_link_libraries(
     ${Boost_SYSTEM_LIBRARY}
     ${CORESERVICES_LIBRARY}
     ${URIPARSER_LIBRARY}
+    nlohmann_json::nlohmann_json
     ${RT_LIBRARY}
     )
 
diff --git a/indra/newview/CMakeLists.txt b/indra/newview/CMakeLists.txt
index 0d25be520..77e370f81 100644
--- a/indra/newview/CMakeLists.txt
+++ b/indra/newview/CMakeLists.txt
@@ -18,7 +18,6 @@ include(FMODSTUDIO)
 include(GeneratePrecompiledHeader)
 include(GLOD)
 include(Hunspell)
-include(Json)
 include(LLAddBuildTest)
 include(LLAppearance)
 include(LLAudio)
@@ -63,7 +62,6 @@ include_directories(
     ${STATEMACHINE_INCLUDE_DIRS}
     ${DBUSGLIB_INCLUDE_DIRS}
     ${ZLIB_INCLUDE_DIRS}
-    ${JSON_INCLUDE_DIR}
     ${GLOD_INCLUDE_DIR}
     ${LLAUDIO_INCLUDE_DIRS}
     ${LLCHARACTER_INCLUDE_DIRS}
@@ -1710,6 +1708,7 @@ target_link_libraries(${VIEWER_BINARY_NAME}
     ${LLAPPEARANCE_LIBRARIES}
     absl::flat_hash_map
     absl::node_hash_map
+    nlohmann_json::nlohmann_json
     ${FMT_LIBRARY}
     )