diff --git a/android/location_api/GnssAPIClient.cpp b/android/location_api/GnssAPIClient.cpp
index 4d0ca3b1..996bbeea 100644
--- a/android/location_api/GnssAPIClient.cpp
+++ b/android/location_api/GnssAPIClient.cpp
@@ -81,8 +81,10 @@ void GnssAPIClient::gnssUpdateCallbacks(const sp<IGnssCallback>& gpsCb,
 {
     LOC_LOGD("%s]: (%p %p)", __FUNCTION__, &gpsCb, &niCb);
 
+    mMutex.lock();
     mGnssCbIface = gpsCb;
     mGnssNiCbIface = niCb;
+    mMutex.unlock();
 
     LocationCallbacks locationCallbacks;
     memset(&locationCallbacks, 0, sizeof(LocationCallbacks));
@@ -278,7 +280,10 @@ void GnssAPIClient::onCapabilitiesCb(LocationCapabilitiesMask capabilitiesMask)
     LOC_LOGD("%s]: (%02x)", __FUNCTION__, capabilitiesMask);
     mLocationCapabilitiesMask = capabilitiesMask;
     mLocationCapabilitiesCached = true;
-    sp<IGnssCallback> gnssCbIface = mGnssCbIface;
+
+    mMutex.lock();
+    auto gnssCbIface(mGnssCbIface);
+    mMutex.unlock();
 
     if (gnssCbIface != nullptr) {
         uint32_t data = 0;
@@ -322,7 +327,9 @@ void GnssAPIClient::onCapabilitiesCb(LocationCapabilitiesMask capabilitiesMask)
 void GnssAPIClient::onTrackingCb(Location location)
 {
     LOC_LOGD("%s]: (flags: %02x)", __FUNCTION__, location.flags);
-    sp<IGnssCallback> gnssCbIface = mGnssCbIface;
+    mMutex.lock();
+    auto gnssCbIface(mGnssCbIface);
+    mMutex.unlock();
 
     if (gnssCbIface != nullptr) {
         GnssLocation gnssLocation;
@@ -338,7 +345,9 @@ void GnssAPIClient::onTrackingCb(Location location)
 void GnssAPIClient::onGnssNiCb(uint32_t id, GnssNiNotification gnssNiNotification)
 {
     LOC_LOGD("%s]: (id: %d)", __FUNCTION__, id);
-    sp<IGnssNiCallback> gnssNiCbIface = mGnssNiCbIface;
+    mMutex.lock();
+    auto gnssNiCbIface(mGnssNiCbIface);
+    mMutex.unlock();
 
     if (gnssNiCbIface == nullptr) {
         LOC_LOGE("%s]: mGnssNiCbIface is nullptr", __FUNCTION__);
@@ -415,7 +424,9 @@ void GnssAPIClient::onGnssNiCb(uint32_t id, GnssNiNotification gnssNiNotificatio
 void GnssAPIClient::onGnssSvCb(GnssSvNotification gnssSvNotification)
 {
     LOC_LOGD("%s]: (count: %zu)", __FUNCTION__, gnssSvNotification.count);
-    sp<IGnssCallback> gnssCbIface = mGnssCbIface;
+    mMutex.lock();
+    auto gnssCbIface(mGnssCbIface);
+    mMutex.unlock();
 
     if (gnssCbIface != nullptr) {
         IGnssCallback::GnssSvStatus svStatus;
@@ -430,7 +441,9 @@ void GnssAPIClient::onGnssSvCb(GnssSvNotification gnssSvNotification)
 
 void GnssAPIClient::onGnssNmeaCb(GnssNmeaNotification gnssNmeaNotification)
 {
-    sp<IGnssCallback> gnssCbIface = mGnssCbIface;
+    mMutex.lock();
+    auto gnssCbIface(mGnssCbIface);
+    mMutex.unlock();
 
     if (gnssCbIface != nullptr) {
         android::hardware::hidl_string nmeaString;
@@ -447,7 +460,9 @@ void GnssAPIClient::onGnssNmeaCb(GnssNmeaNotification gnssNmeaNotification)
 void GnssAPIClient::onStartTrackingCb(LocationError error)
 {
     LOC_LOGD("%s]: (%d)", __FUNCTION__, error);
-    sp<IGnssCallback> gnssCbIface = mGnssCbIface;
+    mMutex.lock();
+    auto gnssCbIface(mGnssCbIface);
+    mMutex.unlock();
 
     if (error == LOCATION_ERROR_SUCCESS && gnssCbIface != nullptr) {
         auto r = gnssCbIface->gnssStatusCb(IGnssCallback::GnssStatusValue::ENGINE_ON);
@@ -466,7 +481,9 @@ void GnssAPIClient::onStartTrackingCb(LocationError error)
 void GnssAPIClient::onStopTrackingCb(LocationError error)
 {
     LOC_LOGD("%s]: (%d)", __FUNCTION__, error);
-    sp<IGnssCallback> gnssCbIface = mGnssCbIface;
+    mMutex.lock();
+    auto gnssCbIface(mGnssCbIface);
+    mMutex.unlock();
 
     if (error == LOCATION_ERROR_SUCCESS && gnssCbIface != nullptr) {
         auto r = gnssCbIface->gnssStatusCb(IGnssCallback::GnssStatusValue::SESSION_END);
diff --git a/android/location_api/GnssAPIClient.h b/android/location_api/GnssAPIClient.h
index 295a9e9b..b5cffb1e 100644
--- a/android/location_api/GnssAPIClient.h
+++ b/android/location_api/GnssAPIClient.h
@@ -30,7 +30,7 @@
 #ifndef GNSS_API_CLINET_H
 #define GNSS_API_CLINET_H
 
-
+#include <mutex>
 #include <android/hardware/gnss/1.0/IGnss.h>
 #include <android/hardware/gnss/1.0/IGnssCallback.h>
 #include <android/hardware/gnss/1.0/IGnssNiCallback.h>
@@ -91,11 +91,10 @@ public:
 private:
     sp<IGnssCallback> mGnssCbIface;
     sp<IGnssNiCallback> mGnssNiCbIface;
-
+    std::mutex mMutex;
     LocationAPIControlClient* mControlClient;
     LocationCapabilitiesMask mLocationCapabilitiesMask;
     bool mLocationCapabilitiesCached;
-
     LocationOptions mLocationOptions;
 };
 
diff --git a/android/location_api/MeasurementAPIClient.cpp b/android/location_api/MeasurementAPIClient.cpp
index dd7ceac5..731c7eda 100644
--- a/android/location_api/MeasurementAPIClient.cpp
+++ b/android/location_api/MeasurementAPIClient.cpp
@@ -66,7 +66,9 @@ MeasurementAPIClient::measurementSetCallback(const sp<IGnssMeasurementCallback>&
 {
     LOC_LOGD("%s]: (%p)", __FUNCTION__, &callback);
 
+    mMutex.lock();
     mGnssMeasurementCbIface = callback;
+    mMutex.unlock();
 
     LocationCallbacks locationCallbacks;
     memset(&locationCallbacks, 0, sizeof(LocationCallbacks));
@@ -116,10 +118,14 @@ void MeasurementAPIClient::onGnssMeasurementsCb(
     LOC_LOGD("%s]: (count: %zu active: %zu)",
             __FUNCTION__, gnssMeasurementsNotification.count, mTracking);
     if (mTracking) {
-        if (mGnssMeasurementCbIface != nullptr) {
+        mMutex.lock();
+        auto gnssMeasurementCbIface(mGnssMeasurementCbIface);
+        mMutex.unlock();
+
+        if (gnssMeasurementCbIface != nullptr) {
             IGnssMeasurementCallback::GnssData gnssData;
             convertGnssData(gnssMeasurementsNotification, gnssData);
-            auto r = mGnssMeasurementCbIface->GnssMeasurementCb(gnssData);
+            auto r = gnssMeasurementCbIface->GnssMeasurementCb(gnssData);
             if (!r.isOk()) {
                 LOC_LOGE("%s] Error from GnssMeasurementCb description=%s",
                     __func__, r.description().c_str());
diff --git a/android/location_api/MeasurementAPIClient.h b/android/location_api/MeasurementAPIClient.h
index 422564d4..8de13264 100644
--- a/android/location_api/MeasurementAPIClient.h
+++ b/android/location_api/MeasurementAPIClient.h
@@ -30,7 +30,7 @@
 #ifndef MEASUREMENT_API_CLINET_H
 #define MEASUREMENT_API_CLINET_H
 
-
+#include <mutex>
 #include <android/hardware/gnss/1.0/IGnssMeasurement.h>
 #include <android/hardware/gnss/1.0/IGnssMeasurementCallback.h>
 #include <LocationAPIClientBase.h>
@@ -63,7 +63,7 @@ public:
 
 private:
     sp<IGnssMeasurementCallback> mGnssMeasurementCbIface;
-
+    std::mutex mMutex;
     bool mTracking;
 };