diff --git a/dts/arm/st/f3/stm32f303Xb.dtsi b/dts/arm/st/f3/stm32f303Xb.dtsi
new file mode 100644
index 00000000000..040566c0b22
--- /dev/null
+++ b/dts/arm/st/f3/stm32f303Xb.dtsi
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2023 Martin Gritzan
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <mem.h>
+#include <st/f3/stm32f303.dtsi>
+
+/ {
+	ccm0: memory@10000000 {
+		compatible = "zephyr,memory-region", "st,stm32-ccm";
+		reg = <0x10000000 DT_SIZE_K(8)>;
+		zephyr,memory-region = "CCM";
+	};
+
+	sram0: memory@20000000 {
+		reg = <0x20000000 DT_SIZE_K(32)>;
+	};
+
+	soc {
+		flash-controller@40022000 {
+			flash0: flash@8000000 {
+				reg = <0x08000000 DT_SIZE_K(128)>;
+			};
+		};
+
+		dma2: dma@40020400 {
+			compatible = "st,stm32-dma-v2bis";
+			#dma-cells = <2>;
+			reg = <0x40020400 0x400>;
+			clocks = <&rcc STM32_CLOCK_BUS_AHB1 0x2>;
+			interrupts = <56 0 57 0 58 0 59 0 60 0>;
+			status = "disabled";
+		};
+
+		rtc@40002800 {
+			bbram: backup_regs {
+				compatible = "st,stm32-bbram";
+				st,backup-regs = <16>;
+				status = "disabled";
+			};
+		};
+	};
+};
diff --git a/dts/arm/st/f3/stm32f303Xc.dtsi b/dts/arm/st/f3/stm32f303Xc.dtsi
index fd857c1a8fd..76131f72349 100644
--- a/dts/arm/st/f3/stm32f303Xc.dtsi
+++ b/dts/arm/st/f3/stm32f303Xc.dtsi
@@ -1,45 +1,16 @@
 /*
- * Copyright (c) 2018 Linaro Limited
+ * Copyright (c) 2023 Martin Gritzan
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #include <mem.h>
-#include <st/f3/stm32f303.dtsi>
+#include <st/f3/stm32f303Xb.dtsi>
 
-/ {
-	ccm0: memory@10000000 {
-		compatible = "zephyr,memory-region", "st,stm32-ccm";
-		reg = <0x10000000 DT_SIZE_K(8)>;
-		zephyr,memory-region = "CCM";
-	};
-
-	sram0: memory@20000000 {
-		reg = <0x20000000 DT_SIZE_K(40)>;
-	};
-
-	soc {
-		flash-controller@40022000 {
-			flash0: flash@8000000 {
-				reg = <0x08000000 DT_SIZE_K(256)>;
-			};
-		};
-
-		dma2: dma@40020400 {
-			compatible = "st,stm32-dma-v2bis";
-			#dma-cells = <2>;
-			reg = <0x40020400 0x400>;
-			clocks = <&rcc STM32_CLOCK_BUS_AHB1 0x2>;
-			interrupts = <56 0 57 0 58 0 59 0 60 0>;
-			status = "disabled";
-		};
-
-		rtc@40002800 {
-			bbram: backup_regs {
-				compatible = "st,stm32-bbram";
-				st,backup-regs = <16>;
-				status = "disabled";
-			};
-		};
-	};
+&sram0 {
+	reg = <0x20000000 DT_SIZE_K(40)>;
+};
+
+&flash0 {
+	reg = <0x08000000 DT_SIZE_K(256)>;
 };
diff --git a/soc/arm/st_stm32/stm32f3/Kconfig.defconfig.stm32f303x(b-c) b/soc/arm/st_stm32/stm32f3/Kconfig.defconfig.stm32f303x(b-c)
new file mode 100644
index 00000000000..752bef89690
--- /dev/null
+++ b/soc/arm/st_stm32/stm32f3/Kconfig.defconfig.stm32f303x(b-c)
@@ -0,0 +1,16 @@
+# ST Microelectronics STM32F303XC MCU
+
+# Copyright (c) 2016 RnDity Sp. z o.o.
+# SPDX-License-Identifier: Apache-2.0
+
+# The HAL expects STM32F302XC to be defined for both the xB and xC variants (only RAM- and Flash-
+# size differ).
+if SOC_STM32F303XB || SOC_STM32F303XC
+
+config SOC
+	default "stm32f303xc"
+
+config NUM_IRQS
+	default 82
+
+endif # SOC_STM32F303XB || SOC_STM32F303XC
diff --git a/soc/arm/st_stm32/stm32f3/Kconfig.defconfig.stm32f303xc b/soc/arm/st_stm32/stm32f3/Kconfig.defconfig.stm32f303xc
deleted file mode 100644
index 875ed373a69..00000000000
--- a/soc/arm/st_stm32/stm32f3/Kconfig.defconfig.stm32f303xc
+++ /dev/null
@@ -1,14 +0,0 @@
-# ST Microelectronics STM32F303XC MCU
-
-# Copyright (c) 2016 RnDity Sp. z o.o.
-# SPDX-License-Identifier: Apache-2.0
-
-if SOC_STM32F303XC
-
-config SOC
-	default "stm32f303xc"
-
-config NUM_IRQS
-	default 82
-
-endif # SOC_STM32F303XC
diff --git a/soc/arm/st_stm32/stm32f3/Kconfig.soc b/soc/arm/st_stm32/stm32f3/Kconfig.soc
index 6dde4dfd8cf..20af2538ba5 100644
--- a/soc/arm/st_stm32/stm32f3/Kconfig.soc
+++ b/soc/arm/st_stm32/stm32f3/Kconfig.soc
@@ -17,6 +17,10 @@ config SOC_STM32F302XC
 config SOC_STM32F303X8
 	bool "STM32F303X8"
 
+config SOC_STM32F303XB
+	bool "STM32F303XB"
+	select CPU_HAS_ARM_MPU
+
 config SOC_STM32F303XC
 	bool "STM32F303XC"
 	select CPU_HAS_ARM_MPU