diff --git a/arch/arm/include/arm/irq.h b/arch/arm/include/arm/irq.h
index 6c7f3aecc07..376288220e0 100644
--- a/arch/arm/include/arm/irq.h
+++ b/arch/arm/include/arm/irq.h
@@ -84,7 +84,11 @@
 #define REG_V7              REG_R10
 #define REG_SB              REG_R9
 #define REG_SL              REG_R10
-#define REG_FP              REG_R11
+#ifdef CONFIG_ARM_THUMB
+  #define REG_FP            REG_R7
+#else
+  #define REG_FP            REG_R11
+#endif /* CONFIG_ARM_THUMB */
 #define REG_IP              REG_R12
 #define REG_SP              REG_R13
 #define REG_LR              REG_R14
diff --git a/arch/arm/include/armv6-m/irq.h b/arch/arm/include/armv6-m/irq.h
index 9d23cc15271..104828b26ca 100644
--- a/arch/arm/include/armv6-m/irq.h
+++ b/arch/arm/include/armv6-m/irq.h
@@ -119,7 +119,7 @@
 #define REG_V7              REG_R10
 #define REG_SB              REG_R9
 #define REG_SL              REG_R10
-#define REG_FP              REG_R11
+#define REG_FP              REG_R7
 #define REG_IP              REG_R12
 #define REG_SP              REG_R13
 #define REG_LR              REG_R14
diff --git a/arch/arm/include/armv7-a/irq.h b/arch/arm/include/armv7-a/irq.h
index c954408be2e..7bbc7870cde 100644
--- a/arch/arm/include/armv7-a/irq.h
+++ b/arch/arm/include/armv7-a/irq.h
@@ -183,7 +183,11 @@
 #define REG_V7              REG_R10
 #define REG_SB              REG_R9
 #define REG_SL              REG_R10
-#define REG_FP              REG_R11
+#ifdef CONFIG_ARM_THUMB
+  #define REG_FP            REG_R7
+#else
+  #define REG_FP            REG_R11
+#endif /* CONFIG_ARM_THUMB */
 #define REG_IP              REG_R12
 #define REG_SP              REG_R13
 #define REG_LR              REG_R14
diff --git a/arch/arm/include/armv7-m/irq.h b/arch/arm/include/armv7-m/irq.h
index 3ba7c7308a8..96fd94c1f04 100644
--- a/arch/arm/include/armv7-m/irq.h
+++ b/arch/arm/include/armv7-m/irq.h
@@ -75,7 +75,7 @@
 #define REG_V7              REG_R10
 #define REG_SB              REG_R9
 #define REG_SL              REG_R10
-#define REG_FP              REG_R11
+#define REG_FP              REG_R7
 #define REG_IP              REG_R12
 #define REG_SP              REG_R13
 #define REG_LR              REG_R14
diff --git a/arch/arm/include/armv7-r/irq.h b/arch/arm/include/armv7-r/irq.h
index bf502a4a149..5acced1f555 100644
--- a/arch/arm/include/armv7-r/irq.h
+++ b/arch/arm/include/armv7-r/irq.h
@@ -183,7 +183,11 @@
 #define REG_V7              REG_R10
 #define REG_SB              REG_R9
 #define REG_SL              REG_R10
-#define REG_FP              REG_R11
+#ifdef CONFIG_ARM_THUMB
+  #define REG_FP            REG_R7
+#else
+  #define REG_FP            REG_R11
+#endif /* CONFIG_ARM_THUMB */
 #define REG_IP              REG_R12
 #define REG_SP              REG_R13
 #define REG_LR              REG_R14
diff --git a/arch/arm/include/armv8-m/irq.h b/arch/arm/include/armv8-m/irq.h
index 8898f30ef39..a89de9078ca 100644
--- a/arch/arm/include/armv8-m/irq.h
+++ b/arch/arm/include/armv8-m/irq.h
@@ -75,7 +75,7 @@
 #define REG_V7              REG_R10
 #define REG_SB              REG_R9
 #define REG_SL              REG_R10
-#define REG_FP              REG_R11
+#define REG_FP              REG_R7
 #define REG_IP              REG_R12
 #define REG_SP              REG_R13
 #define REG_LR              REG_R14