diff --git a/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java b/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java
index 0793599ac57..0b2828200aa 100644
--- a/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java
+++ b/hapi-fhir-base/src/main/java/ca/uhn/fhir/util/BundleUtil.java
@@ -130,6 +130,16 @@ public class BundleUtil {
 		return null;
 	}
 
+	public static void setBundleType(FhirContext theContext, IBaseBundle theBundle, String theType) {
+		RuntimeResourceDefinition def = theContext.getResourceDefinition(theBundle);
+		BaseRuntimeChildDefinition entryChild = def.getChildByName("type");
+		BaseRuntimeElementDefinition<?> element = entryChild.getChildByName("type");
+		IPrimitiveType<?> typeInstance = (IPrimitiveType<?>) element.newInstance(entryChild.getInstanceConstructorArguments());
+		typeInstance.setValueAsString(theType);
+
+		entryChild.getMutator().setValue(theBundle, typeInstance);
+	}
+
 	public static Integer getTotal(FhirContext theContext, IBaseBundle theBundle) {
 		RuntimeResourceDefinition def = theContext.getResourceDefinition(theBundle);
 		BaseRuntimeChildDefinition entryChild = def.getChildByName("total");
diff --git a/hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/5_3_0/2237-support-ibasebundle-for-xact-method-param.yaml b/hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/5_3_0/2237-support-ibasebundle-for-xact-method-param.yaml
new file mode 100644
index 00000000000..cb78763b8d0
--- /dev/null
+++ b/hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/5_3_0/2237-support-ibasebundle-for-xact-method-param.yaml
@@ -0,0 +1,5 @@
+---
+type: add
+issue: 2237
+title: "It is now possible to use a parameter of type `IBaseResource` or `IBaseBundle` as the parameter
+   on a @Transaction method in a plain server."
diff --git a/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/TransactionParameter.java b/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/TransactionParameter.java
index d191ce5f8a1..e93ef4bfcb5 100644
--- a/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/TransactionParameter.java
+++ b/hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/method/TransactionParameter.java
@@ -50,7 +50,7 @@ public class TransactionParameter implements IParameter {
 
 	private String createParameterTypeError(Method theMethod) {
 		return "Method '" + theMethod.getName() + "' in type '" + theMethod.getDeclaringClass().getCanonicalName() + "' is annotated with @" + TransactionParam.class.getName()
-			+ " but is not of type List<" + IResource.class.getCanonicalName() + "> or Bundle";
+			+ " but is not of type Bundle, IBaseResource, IBaseBundle, or List<" + IResource.class.getCanonicalName() + ">";
 	}
 
 	@Override
@@ -66,10 +66,13 @@ public class TransactionParameter implements IParameter {
 			if ("Bundle".equals(def.getName())) {
 				myParamStyle = ParamStyle.RESOURCE_BUNDLE;
 				myResourceBundleType = parameterType;
-			} else {
-				throw new ConfigurationException(createParameterTypeError(theMethod));
+				return;
 			}
-		} else {
+		} else if (theParameterType.equals(IBaseResource.class) || theParameterType.equals(IBaseBundle.class)) {
+			myParamStyle = ParamStyle.RESOURCE_BUNDLE;
+			myResourceBundleType = myContext.getResourceDefinition("Bundle").getImplementingClass();
+			return;
+		} else if (theInnerCollectionType != null) {
 			if (theInnerCollectionType.equals(List.class) == false) {
 				throw new ConfigurationException(createParameterTypeError(theMethod));
 			}
@@ -77,7 +80,10 @@ public class TransactionParameter implements IParameter {
 				throw new ConfigurationException(createParameterTypeError(theMethod));
 			}
 			myParamStyle = ParamStyle.RESOURCE_LIST;
+			return;
 		}
+
+		throw new ConfigurationException(createParameterTypeError(theMethod));
 	}
 
 	@Override
diff --git a/hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/rest/server/TransactionServerTest.java b/hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/rest/server/TransactionServerTest.java
new file mode 100644
index 00000000000..d2c8b5094c0
--- /dev/null
+++ b/hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/rest/server/TransactionServerTest.java
@@ -0,0 +1,43 @@
+package ca.uhn.fhir.rest.server;
+
+import ca.uhn.fhir.context.FhirVersionEnum;
+import ca.uhn.fhir.rest.annotation.Transaction;
+import ca.uhn.fhir.rest.annotation.TransactionParam;
+import ca.uhn.fhir.test.utilities.server.RestfulServerExtension;
+import org.hl7.fhir.instance.model.api.IBaseBundle;
+import org.hl7.fhir.r4.model.Bundle;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class TransactionServerTest {
+
+	@RegisterExtension
+	public RestfulServerExtension myServerRule = new RestfulServerExtension(FhirVersionEnum.R4);
+
+
+	@Test
+	public void testTransactionParamIsInterface() {
+
+		class MyProvider {
+
+			@Transaction
+			public IBaseBundle transaction(@TransactionParam IBaseBundle theInput) {
+				return theInput;
+			}
+
+		}
+
+		myServerRule.getRestfulServer().registerProvider(new MyProvider());
+
+		Bundle input = new Bundle();
+		input.setId("ABC");
+		input.setType(Bundle.BundleType.TRANSACTION);
+		Bundle output = myServerRule.getFhirClient().transaction().withBundle(input).execute();
+
+		assertEquals("ABC", output.getIdElement().getIdPart());
+
+	}
+
+}
diff --git a/hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/util/bundle/BundleUtilTest.java b/hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/util/bundle/BundleUtilTest.java
index 0b887d0eef0..5801947ab06 100644
--- a/hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/util/bundle/BundleUtilTest.java
+++ b/hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/util/bundle/BundleUtilTest.java
@@ -45,6 +45,15 @@ public class BundleUtilTest {
 		assertEquals(null, BundleUtil.getTotal(ourCtx, b));
 	}
 
+	@Test
+	public void testSetType() {
+		Bundle b = new Bundle();
+		BundleUtil.setBundleType(ourCtx, b, "transaction");
+		assertEquals(Bundle.BundleType.TRANSACTION, b.getType());
+		assertEquals("transaction", b.getTypeElement().getValueAsString());
+	}
+
+
 	@Test
 	public void toListOfResourcesOfTypeTest() {
 		Bundle bundle = new Bundle();