diff --git a/include/spdlog/async.h b/include/spdlog/async.h
index e96abd19..9d6bf1d8 100644
--- a/include/spdlog/async.h
+++ b/include/spdlog/async.h
@@ -14,9 +14,9 @@
 // This is because each message in the queue holds a shared_ptr to the
 // originating logger.
 
-#include <spdlog/async_logger.h>
-#include <spdlog/details/registry.h>
-#include <spdlog/details/thread_pool.h>
+#include "async_logger.h"
+#include "details/registry.h"
+#include "details/thread_pool.h"
 
 #include <functional>
 #include <memory>
diff --git a/include/spdlog/async_logger.h b/include/spdlog/async_logger.h
index 299e59dc..476621d7 100644
--- a/include/spdlog/async_logger.h
+++ b/include/spdlog/async_logger.h
@@ -12,9 +12,9 @@
 //    2. Push a new copy of the message to a queue (or block the caller until
 //    space is available in the queue)
 // Upon destruction, logs all remaining messages in the queue before
-// destructing..
+// destructing
 
-#include <spdlog/logger.h>
+#include "logger.h"
 
 namespace spdlog {
 
diff --git a/include/spdlog/cfg/argv.h b/include/spdlog/cfg/argv.h
index 7de2f83e..19e17e3c 100644
--- a/include/spdlog/cfg/argv.h
+++ b/include/spdlog/cfg/argv.h
@@ -2,8 +2,8 @@
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
 #pragma once
-#include <spdlog/cfg/helpers.h>
-#include <spdlog/details/registry.h>
+#include "helpers.h"
+#include "../details/registry.h"
 
 //
 // Init log levels using each argv entry that starts with "SPDLOG_LEVEL="
diff --git a/include/spdlog/cfg/env.h b/include/spdlog/cfg/env.h
index 6e554145..777aee4e 100644
--- a/include/spdlog/cfg/env.h
+++ b/include/spdlog/cfg/env.h
@@ -2,9 +2,9 @@
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
 #pragma once
-#include <spdlog/cfg/helpers.h>
-#include <spdlog/details/os.h>
-#include <spdlog/details/registry.h>
+#include "helpers.h"
+#include "../details/os.h"
+#include "../details/registry.h"
 
 //
 // Init levels and patterns from env variables SPDLOG_LEVEL
diff --git a/include/spdlog/cfg/helpers.h b/include/spdlog/cfg/helpers.h
index d43ef3b1..6933d777 100644
--- a/include/spdlog/cfg/helpers.h
+++ b/include/spdlog/cfg/helpers.h
@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include <spdlog/common.h>
+#include "../common.h"
 #include <unordered_map>
 
 namespace spdlog {
diff --git a/include/spdlog/common.h b/include/spdlog/common.h
index 40779770..b97ba6e5 100644
--- a/include/spdlog/common.h
+++ b/include/spdlog/common.h
@@ -2,8 +2,8 @@
 // Distributed under the MIT License (http://opensource.org/licenses/MIT)
 
 #pragma once
-#include <spdlog/details/null_mutex.h>
-#include <spdlog/tweakme.h>
+#include "details/null_mutex.h"
+#include "tweakme.h"
 
 #include <array>
 #include <atomic>
@@ -51,13 +51,13 @@
     #define SPDLOG_API
 #endif
 
-#include <spdlog/fmt/fmt.h>
+#include "fmt/fmt.h"
 
 #if !defined(SPDLOG_USE_STD_FORMAT) && \
     FMT_VERSION >= 80000  // backward compatibility with fmt versions older than 8
     #define SPDLOG_FMT_RUNTIME(format_string) fmt::runtime(format_string)
     #if defined(SPDLOG_WCHAR_FILENAMES)
-        #include <spdlog/fmt/xchar.h>
+        #include "fmt/xchar.h"
     #endif
 #else
     #define SPDLOG_FMT_RUNTIME(format_string) format_string
diff --git a/include/spdlog/details/udp_client-windows.h b/include/spdlog/details/udp_client-windows.h
index 64ae411e..d6b6cb59 100644
--- a/include/spdlog/details/udp_client-windows.h
+++ b/include/spdlog/details/udp_client-windows.h
@@ -6,10 +6,10 @@
 // Helper RAII over winsock udp client socket.
 // Will throw on construction if socket creation failed.
 
-#include "../common.h"
 #include "os.h"
+#include "windows_include.h"
+#include "../common.h"
 
-#include <spdlog/details/windows_include.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string>
diff --git a/include/spdlog/fmt/bin_to_hex.h b/include/spdlog/fmt/bin_to_hex.h
index e7c3fefb..376e8319 100644
--- a/include/spdlog/fmt/bin_to_hex.h
+++ b/include/spdlog/fmt/bin_to_hex.h
@@ -6,7 +6,7 @@
 #pragma once
 
 #include <cctype>
-#include <spdlog/common.h>
+#include "../common.h"
 
 #if defined(__has_include)
     #if __has_include(<version>)
diff --git a/include/spdlog/fmt/chrono.h b/include/spdlog/fmt/chrono.h
index e991b775..2284cda9 100644
--- a/include/spdlog/fmt/chrono.h
+++ b/include/spdlog/fmt/chrono.h
@@ -10,7 +10,7 @@
 
 #if !defined(SPDLOG_USE_STD_FORMAT)
     #if !defined(SPDLOG_FMT_EXTERNAL)
-        #include <spdlog/fmt/bundled/chrono.h>
+        #include "../fmt/bundled/chrono.h"
     #else
         #include <fmt/chrono.h>
     #endif
diff --git a/include/spdlog/fmt/compile.h b/include/spdlog/fmt/compile.h
index 150be096..2034f5cf 100644
--- a/include/spdlog/fmt/compile.h
+++ b/include/spdlog/fmt/compile.h
@@ -10,7 +10,7 @@
 
 #if !defined(SPDLOG_USE_STD_FORMAT)
     #if !defined(SPDLOG_FMT_EXTERNAL)
-        #include <spdlog/fmt/bundled/compile.h>
+            #include "../fmt/bundled/compile.h"
     #else
         #include <fmt/compile.h>
     #endif
diff --git a/include/spdlog/fmt/fmt.h b/include/spdlog/fmt/fmt.h
index 9d986c09..50cb9aed 100644
--- a/include/spdlog/fmt/fmt.h
+++ b/include/spdlog/fmt/fmt.h
@@ -13,8 +13,8 @@
 #if defined(SPDLOG_USE_STD_FORMAT)  // SPDLOG_USE_STD_FORMAT is defined - use std::format
     #include <format>
 #elif !defined(SPDLOG_FMT_EXTERNAL)
-    #include <spdlog/fmt/bundled/core.h>
-    #include <spdlog/fmt/bundled/format.h>
+    #include "bundled/core.h"
+    #include "bundled/format.h"
 #else  // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
     #include <fmt/core.h>
     #include <fmt/format.h>
diff --git a/include/spdlog/fmt/ostr.h b/include/spdlog/fmt/ostr.h
index dbb159d2..9ee7e28a 100644
--- a/include/spdlog/fmt/ostr.h
+++ b/include/spdlog/fmt/ostr.h
@@ -10,7 +10,7 @@
 
 #if !defined(SPDLOG_USE_STD_FORMAT)
     #if !defined(SPDLOG_FMT_EXTERNAL)
-        #include <spdlog/fmt/bundled/ostream.h>
+            #include "../fmt/bundled/ostream.h"
     #else
         #include <fmt/ostream.h>
     #endif
diff --git a/include/spdlog/fmt/ranges.h b/include/spdlog/fmt/ranges.h
index f3971363..a7a75e66 100644
--- a/include/spdlog/fmt/ranges.h
+++ b/include/spdlog/fmt/ranges.h
@@ -10,7 +10,7 @@
 
 #if !defined(SPDLOG_USE_STD_FORMAT)
     #if !defined(SPDLOG_FMT_EXTERNAL)
-        #include <spdlog/fmt/bundled/ranges.h>
+        #include "../fmt/bundled/ranges.h"
     #else
         #include <fmt/ranges.h>
     #endif
diff --git a/include/spdlog/fmt/std.h b/include/spdlog/fmt/std.h
index 2bf8f7f4..ae426a08 100644
--- a/include/spdlog/fmt/std.h
+++ b/include/spdlog/fmt/std.h
@@ -11,7 +11,7 @@
 
 #if !defined(SPDLOG_USE_STD_FORMAT)
     #if !defined(SPDLOG_FMT_EXTERNAL)
-        #include <spdlog/fmt/bundled/std.h>
+        #include "../fmt/bundled/std.h"
     #else
         #include <fmt/std.h>
     #endif
diff --git a/include/spdlog/fmt/xchar.h b/include/spdlog/fmt/xchar.h
index fd15f070..499dd797 100644
--- a/include/spdlog/fmt/xchar.h
+++ b/include/spdlog/fmt/xchar.h
@@ -10,7 +10,7 @@
 
 #if !defined(SPDLOG_USE_STD_FORMAT)
     #if !defined(SPDLOG_FMT_EXTERNAL)
-        #include <spdlog/fmt/bundled/xchar.h>
+        #include "../fmt/bundled/xchar.h"
     #else
         #include <fmt/xchar.h>
     #endif
diff --git a/include/spdlog/formatter.h b/include/spdlog/formatter.h
index 4d482f82..4ebdf910 100644
--- a/include/spdlog/formatter.h
+++ b/include/spdlog/formatter.h
@@ -3,8 +3,8 @@
 
 #pragma once
 
-#include <spdlog/details/log_msg.h>
-#include <spdlog/fmt/fmt.h>
+#include "details/log_msg.h"
+#include "fmt/fmt.h"
 
 namespace spdlog {
 
diff --git a/include/spdlog/logger.h b/include/spdlog/logger.h
index a912a138..0915d1ac 100644
--- a/include/spdlog/logger.h
+++ b/include/spdlog/logger.h
@@ -14,9 +14,9 @@
 // The use of private formatter per sink provides the opportunity to cache some
 // formatted data, and support for different format per sink.
 
-#include <spdlog/common.h>
-#include <spdlog/details/log_msg.h>
-#include <spdlog/sinks/sink.h>
+#include "common.h"
+#include "details/log_msg.h"
+#include "sinks/sink.h"
 
 #include <cassert>
 #include <vector>
diff --git a/include/spdlog/pattern_formatter.h b/include/spdlog/pattern_formatter.h
index 55479404..10a90c3d 100644
--- a/include/spdlog/pattern_formatter.h
+++ b/include/spdlog/pattern_formatter.h
@@ -3,10 +3,10 @@
 
 #pragma once
 
-#include <spdlog/common.h>
-#include <spdlog/details/log_msg.h>
-#include <spdlog/details/os.h>
-#include <spdlog/formatter.h>
+#include "common.h"
+#include "details/log_msg.h"
+#include "details/os.h"
+#include "formatter.h"
 
 #include <chrono>
 #include <ctime>
diff --git a/include/spdlog/spdlog.h b/include/spdlog/spdlog.h
index 60dcf49a..8bf8e56d 100644
--- a/include/spdlog/spdlog.h
+++ b/include/spdlog/spdlog.h
@@ -9,11 +9,11 @@
 
 #pragma once
 
-#include <spdlog/common.h>
-#include <spdlog/details/registry.h>
-#include <spdlog/details/synchronous_factory.h>
-#include <spdlog/logger.h>
-#include <spdlog/version.h>
+#include "common.h"
+#include "logger.h"
+#include "version.h"
+#include "details/registry.h"
+#include "details/synchronous_factory.h"
 
 #include <chrono>
 #include <functional>
diff --git a/include/spdlog/stopwatch.h b/include/spdlog/stopwatch.h
index d19e591f..ad40f95d 100644
--- a/include/spdlog/stopwatch.h
+++ b/include/spdlog/stopwatch.h
@@ -4,7 +4,7 @@
 #pragma once
 
 #include <chrono>
-#include <spdlog/fmt/fmt.h>
+#include "fmt/fmt.h"
 
 // Stopwatch support for spdlog  (using std::chrono::steady_clock).
 // Displays elapsed seconds since construction as double.