diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b1f881b6..77f69f682 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - hci_cmd: support variable length fields and arrayed parameters
 - GAP: ENABLE_EXPLICIT_LINK_KEY_REPLY allows for asynchronous link key lookup by application
 - GAP: gap_set_page_timeout to set Page Timeout
+- GAP: gap_inquiry_set_scan_activity to set Inquiry Scan Activity
 - POSIX: btstack_signal allows to register for callback on signal, e.g. ctrl-c
 - Windows: btstack_stdin_window_register_ctrl_c_callback allows to register for ctrl-c
 - A2DP: allow to register media codec validator for sink and source with:
diff --git a/src/gap.h b/src/gap.h
index 0a6c0035e..d0f6ccb8e 100644
--- a/src/gap.h
+++ b/src/gap.h
@@ -749,6 +749,13 @@ int gap_inquiry_stop(void);
  */
 void gap_inquiry_set_lap(uint32_t lap);
 
+/**
+ * @brief Set Inquiry Scan Activity
+ * @param inquiry_scan_interval range: 0x0012 to 0x1000; only even values are valid, Time = N * 0.625 ms
+ * @param inquiry_scan_window range: 0x0011 to 0x1000; Time = N * 0.625 ms
+ */
+void gap_inquiry_set_activity(uint16_t inquiry_scan_interval, uint16_t inquiry_scan_window);
+
 /**
  * @brief Remote Name Request
  * @param addr
diff --git a/src/hci.c b/src/hci.c
index bb89db308..8d44fed38 100644
--- a/src/hci.c
+++ b/src/hci.c
@@ -1359,6 +1359,12 @@ static void hci_run_gap_tasks_classic(void){
         hci_send_cmd(&hci_write_scan_enable, hci_stack->new_scan_enable_value);
         return;
     }
+    // send write scan activity
+    if ((hci_stack->gap_tasks & GAP_TASK_WRITE_INQUIRY_SCAN_ACTIVITY) != 0) {
+        hci_stack->gap_tasks &= ~GAP_TASK_WRITE_INQUIRY_SCAN_ACTIVITY;
+        hci_send_cmd(&hci_write_inquiry_scan_activity, hci_stack->inquiry_scan_interval, hci_stack->inquiry_scan_window);
+        return;
+    }
 }
 #endif
 
@@ -6398,6 +6404,13 @@ void gap_inquiry_set_lap(uint32_t lap){
     hci_stack->inquiry_lap = lap;
 }
 
+void gap_inquiry_set_activity(uint16_t inquiry_scan_interval, uint16_t inquiry_scan_window){
+    hci_stack->inquiry_scan_interval = inquiry_scan_interval;
+    hci_stack->inquiry_scan_window   = inquiry_scan_window;
+    hci_stack->gap_tasks |= GAP_TASK_WRITE_INQUIRY_SCAN_ACTIVITY;
+    hci_run();
+}
+
 
 /**
  * @brief Remote Name Request
diff --git a/src/hci.h b/src/hci.h
index c89d5f2c3..f77e7a6a4 100644
--- a/src/hci.h
+++ b/src/hci.h
@@ -779,14 +779,15 @@ typedef enum hci_init_state{
 
 } hci_substate_t;
 
-#define GAP_TASK_SET_LOCAL_NAME           0x01
-#define GAP_TASK_SET_EIR_DATA             0x02
-#define GAP_TASK_SET_CLASS_OF_DEVICE      0x04
-#define GAP_TASK_SET_DEFAULT_LINK_POLICY  0x08
-#define GAP_TASK_WRITE_SCAN_ENABLE        0x10
-#define GAP_TASK_WRITE_PAGE_SCAN_ACTIVITY 0x20
-#define GAP_TASK_WRITE_PAGE_SCAN_TYPE     0x40
-#define GAP_TASK_WRITE_PAGE_TIMEOUT       0x80
+#define GAP_TASK_SET_LOCAL_NAME               0x01
+#define GAP_TASK_SET_EIR_DATA                 0x02
+#define GAP_TASK_SET_CLASS_OF_DEVICE          0x04
+#define GAP_TASK_SET_DEFAULT_LINK_POLICY      0x08
+#define GAP_TASK_WRITE_SCAN_ENABLE            0x10
+#define GAP_TASK_WRITE_PAGE_SCAN_ACTIVITY     0x20
+#define GAP_TASK_WRITE_PAGE_SCAN_TYPE         0x40
+#define GAP_TASK_WRITE_PAGE_TIMEOUT           0x80
+#define GAP_TASK_WRITE_INQUIRY_SCAN_ACTIVITY 0x100
 
 enum {
     // Tasks
@@ -897,7 +898,9 @@ typedef struct {
     gap_security_mode_t  gap_security_mode;
 
     uint32_t            inquiry_lap;      // GAP_IAC_GENERAL_INQUIRY or GAP_IAC_LIMITED_INQUIRY
-
+    uint16_t            inquiry_scan_interval;
+    uint16_t            inquiry_scan_window;
+    
     bool                gap_secure_connections_only_mode;
 #endif