diff --git a/cameraserver/src/main/native/include/vision/VisionRunner.inc b/cameraserver/src/main/native/include/vision/VisionRunner.inc
index 9a195ffd56..56cfe695e4 100644
--- a/cameraserver/src/main/native/include/vision/VisionRunner.inc
+++ b/cameraserver/src/main/native/include/vision/VisionRunner.inc
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <functional>
+
 #include "vision/VisionRunner.h"
 
 namespace frc {
diff --git a/cscore/src/main/native/include/cscore_cv.h b/cscore/src/main/native/include/cscore_cv.h
index 6a91accc7f..66cb23e385 100644
--- a/cscore/src/main/native/include/cscore_cv.h
+++ b/cscore/src/main/native/include/cscore_cv.h
@@ -5,6 +5,8 @@
 #ifndef CSCORE_CSCORE_CV_H_
 #define CSCORE_CSCORE_CV_H_
 
+#include <functional>
+
 #include "cscore_c.h"
 
 #ifdef CSCORE_CSCORE_RAW_CV_H_
diff --git a/cscore/src/main/native/include/cscore_oo.h b/cscore/src/main/native/include/cscore_oo.h
index ab09fe7355..f13a6fd977 100644
--- a/cscore/src/main/native/include/cscore_oo.h
+++ b/cscore/src/main/native/include/cscore_oo.h
@@ -5,6 +5,7 @@
 #ifndef CSCORE_CSCORE_OO_H_
 #define CSCORE_CSCORE_OO_H_
 
+#include <functional>
 #include <initializer_list>
 #include <span>
 #include <string>
diff --git a/cscore/src/main/native/include/cscore_oo.inc b/cscore/src/main/native/include/cscore_oo.inc
index ff3540d2aa..18a1df263d 100644
--- a/cscore/src/main/native/include/cscore_oo.inc
+++ b/cscore/src/main/native/include/cscore_oo.inc
@@ -5,6 +5,7 @@
 #ifndef CSCORE_CSCORE_OO_INC_
 #define CSCORE_CSCORE_OO_INC_
 
+#include <functional>
 #include <string>
 #include <string_view>
 #include <utility>
diff --git a/cscore/src/main/native/include/cscore_raw.h b/cscore/src/main/native/include/cscore_raw.h
index 5e1632c096..21f4009ae0 100644
--- a/cscore/src/main/native/include/cscore_raw.h
+++ b/cscore/src/main/native/include/cscore_raw.h
@@ -5,6 +5,8 @@
 #ifndef CSCORE_CSCORE_RAW_H_
 #define CSCORE_CSCORE_RAW_H_
 
+#include <functional>
+
 #include "cscore_c.h"
 
 #ifdef __cplusplus
diff --git a/cscore/src/main/native/include/cscore_raw_cv.h b/cscore/src/main/native/include/cscore_raw_cv.h
index 975fcc91ac..11f42d6c62 100644
--- a/cscore/src/main/native/include/cscore_raw_cv.h
+++ b/cscore/src/main/native/include/cscore_raw_cv.h
@@ -9,6 +9,8 @@
 #error "Cannot include both cscore_cv.h and cscore_raw_cv.h in the same file"
 #endif
 
+#include <functional>
+
 #include <opencv2/core/mat.hpp>
 
 #include "cscore_raw.h"
diff --git a/simulation/halsim_ws_core/src/main/native/include/WSProvider_SimDevice.h b/simulation/halsim_ws_core/src/main/native/include/WSProvider_SimDevice.h
index 3a1ff5f76a..6343e72f7b 100644
--- a/simulation/halsim_ws_core/src/main/native/include/WSProvider_SimDevice.h
+++ b/simulation/halsim_ws_core/src/main/native/include/WSProvider_SimDevice.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <memory>
 #include <string>
 #include <string_view>
diff --git a/simulation/halsim_ws_server/src/test/native/include/WebServerClientTest.h b/simulation/halsim_ws_server/src/test/native/include/WebServerClientTest.h
index cda61ddf65..dc86d89080 100644
--- a/simulation/halsim_ws_server/src/test/native/include/WebServerClientTest.h
+++ b/simulation/halsim_ws_server/src/test/native/include/WebServerClientTest.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <memory>
 #include <string>
 
diff --git a/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h b/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h
index 0d5040bdf7..986a4c30fb 100644
--- a/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h
+++ b/wpilibNewCommands/src/main/native/include/frc2/command/CommandScheduler.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include <concepts>
+#include <functional>
 #include <initializer_list>
 #include <memory>
 #include <span>
diff --git a/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h b/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h
index a42cbc032e..0bec3c34e3 100644
--- a/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h
+++ b/wpilibNewCommands/src/main/native/include/frc2/command/SelectCommand.h
@@ -10,6 +10,7 @@
 #endif
 
 #include <concepts>
+#include <functional>
 #include <memory>
 #include <string>
 #include <unordered_map>
diff --git a/wpilibNewCommands/src/main/native/include/frc2/command/Subsystem.h b/wpilibNewCommands/src/main/native/include/frc2/command/Subsystem.h
index a07a684847..791db7096c 100644
--- a/wpilibNewCommands/src/main/native/include/frc2/command/Subsystem.h
+++ b/wpilibNewCommands/src/main/native/include/frc2/command/Subsystem.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include <concepts>
+#include <functional>
 #include <string>
 #include <utility>
 
diff --git a/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc b/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc
index 2aeff28046..e77294de6c 100644
--- a/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc
+++ b/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <memory>
 #include <utility>
 
diff --git a/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandTestBase.h b/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandTestBase.h
index 9ad59e5081..594ca8e1d2 100644
--- a/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandTestBase.h
+++ b/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandTestBase.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <memory>
 #include <utility>
 
diff --git a/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.h b/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.h
index 691226778d..42e9806a1a 100644
--- a/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.h
+++ b/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include <concepts>
+#include <functional>
 #include <memory>
 #include <string_view>
 
diff --git a/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.inc b/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.inc
index 5a18928e4b..18f983be6a 100644
--- a/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.inc
+++ b/wpilibc/src/main/native/include/frc/smartdashboard/SendableChooser.inc
@@ -5,6 +5,7 @@
 #pragma once
 
 #include <algorithm>
+#include <functional>
 #include <memory>
 #include <string>
 #include <string_view>
diff --git a/wpilibc/src/main/native/include/frc/smartdashboard/SmartDashboard.h b/wpilibc/src/main/native/include/frc/smartdashboard/SmartDashboard.h
index aeb4947f7c..04435f0252 100644
--- a/wpilibc/src/main/native/include/frc/smartdashboard/SmartDashboard.h
+++ b/wpilibc/src/main/native/include/frc/smartdashboard/SmartDashboard.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <memory>
 #include <span>
 #include <string>
diff --git a/wpilibcExamples/src/main/cpp/examples/GearsBot/include/commands/TankDrive.h b/wpilibcExamples/src/main/cpp/examples/GearsBot/include/commands/TankDrive.h
index bf6597d972..932c427d5c 100644
--- a/wpilibcExamples/src/main/cpp/examples/GearsBot/include/commands/TankDrive.h
+++ b/wpilibcExamples/src/main/cpp/examples/GearsBot/include/commands/TankDrive.h
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <functional>
+
 #include <frc2/command/Command.h>
 #include <frc2/command/CommandHelper.h>
 
diff --git a/wpilibcExamples/src/main/cpp/examples/HatchbotTraditional/include/commands/DefaultDrive.h b/wpilibcExamples/src/main/cpp/examples/HatchbotTraditional/include/commands/DefaultDrive.h
index b5cb4f498c..7d58f9ec1a 100644
--- a/wpilibcExamples/src/main/cpp/examples/HatchbotTraditional/include/commands/DefaultDrive.h
+++ b/wpilibcExamples/src/main/cpp/examples/HatchbotTraditional/include/commands/DefaultDrive.h
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <functional>
+
 #include <frc2/command/Command.h>
 #include <frc2/command/CommandHelper.h>
 
diff --git a/wpilibcExamples/src/main/cpp/examples/RomiReference/include/commands/TeleopArcadeDrive.h b/wpilibcExamples/src/main/cpp/examples/RomiReference/include/commands/TeleopArcadeDrive.h
index f5364207f3..fe2e241028 100644
--- a/wpilibcExamples/src/main/cpp/examples/RomiReference/include/commands/TeleopArcadeDrive.h
+++ b/wpilibcExamples/src/main/cpp/examples/RomiReference/include/commands/TeleopArcadeDrive.h
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <functional>
+
 #include <frc2/command/Command.h>
 #include <frc2/command/CommandHelper.h>
 
diff --git a/wpimath/src/main/native/include/frc/estimator/AngleStatistics.h b/wpimath/src/main/native/include/frc/estimator/AngleStatistics.h
index 0512c68cce..026cc67881 100644
--- a/wpimath/src/main/native/include/frc/estimator/AngleStatistics.h
+++ b/wpimath/src/main/native/include/frc/estimator/AngleStatistics.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <numbers>
 
 #include "frc/EigenCore.h"
diff --git a/wpimath/src/main/native/include/frc/estimator/ExtendedKalmanFilter.inc b/wpimath/src/main/native/include/frc/estimator/ExtendedKalmanFilter.inc
index ede7aafa3d..d534196292 100644
--- a/wpimath/src/main/native/include/frc/estimator/ExtendedKalmanFilter.inc
+++ b/wpimath/src/main/native/include/frc/estimator/ExtendedKalmanFilter.inc
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <functional>
+
 #include "Eigen/Cholesky"
 #include "frc/DARE.h"
 #include "frc/StateSpaceUtil.h"
diff --git a/wpimath/src/main/native/include/frc/estimator/UnscentedKalmanFilter.inc b/wpimath/src/main/native/include/frc/estimator/UnscentedKalmanFilter.inc
index 5b9803d64b..7c44e7f526 100644
--- a/wpimath/src/main/native/include/frc/estimator/UnscentedKalmanFilter.inc
+++ b/wpimath/src/main/native/include/frc/estimator/UnscentedKalmanFilter.inc
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <functional>
+
 #include "Eigen/Cholesky"
 #include "frc/StateSpaceUtil.h"
 #include "frc/estimator/UnscentedKalmanFilter.h"
diff --git a/wpimath/src/main/native/include/frc/estimator/UnscentedTransform.h b/wpimath/src/main/native/include/frc/estimator/UnscentedTransform.h
index e28f0941b7..17df925321 100644
--- a/wpimath/src/main/native/include/frc/estimator/UnscentedTransform.h
+++ b/wpimath/src/main/native/include/frc/estimator/UnscentedTransform.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <functional>
 #include <tuple>
 
 #include "Eigen/QR"
diff --git a/wpimath/src/main/native/include/frc/system/LinearSystemLoop.h b/wpimath/src/main/native/include/frc/system/LinearSystemLoop.h
index 1300a82a02..c61531ae08 100644
--- a/wpimath/src/main/native/include/frc/system/LinearSystemLoop.h
+++ b/wpimath/src/main/native/include/frc/system/LinearSystemLoop.h
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <functional>
+
 #include <wpi/SymbolExports.h>
 
 #include "frc/EigenCore.h"
diff --git a/wpinet/src/main/native/include/wpinet/uv/Poll.h b/wpinet/src/main/native/include/wpinet/uv/Poll.h
index 1e638369bc..3ba9a2c5a6 100644
--- a/wpinet/src/main/native/include/wpinet/uv/Poll.h
+++ b/wpinet/src/main/native/include/wpinet/uv/Poll.h
@@ -7,6 +7,7 @@
 
 #include <uv.h>
 
+#include <functional>
 #include <memory>
 
 #include <wpi/Signal.h>