diff --git a/.github/workflows/xml_lint.yml b/.github/workflows/xml_lint.yml
index 6ae7ef0d3..733b83828 100644
--- a/.github/workflows/xml_lint.yml
+++ b/.github/workflows/xml_lint.yml
@@ -12,11 +12,11 @@ on:
       - master
     paths:
       - 'libsel4/**/sel4*.xml'
-      - 'libsel4/**/sel4*.dtd'
+      - 'libsel4/**/sel4*.xsd'
   pull_request:
     paths:
       - 'libsel4/**/sel4*.xml'
-      - 'libsel4/**/sel4*.dtd'
+      - 'libsel4/**/sel4*.xsd'
 
 jobs:
   xmllint:
@@ -29,4 +29,4 @@ jobs:
     - name: run xmllint
       run: |
         find libsel4 -name "sel4*.xml" | \
-        xargs xmllint --dtdvalid libsel4/tools/sel4_idl.dtd --noout
+        xargs xmllint --schema libsel4/tools/sel4_idl.xsd --noout
diff --git a/libsel4/tools/sel4_idl.dtd b/libsel4/tools/sel4_idl.dtd
deleted file mode 100644
index 93e703055..000000000
--- a/libsel4/tools/sel4_idl.dtd
+++ /dev/null
@@ -1,62 +0,0 @@
-<!--
-     Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
-
-     SPDX-License-Identifier: BSD-2-Clause
--->
-
-<!ELEMENT api (struct*,interface*)>
-<!ATTLIST api name CDATA #IMPLIED>
-<!ATTLIST api label_prefix CDATA #IMPLIED>
-
-<!ELEMENT struct (member*)>
-<!ATTLIST struct name CDATA #REQUIRED>
-
-<!ELEMENT member EMPTY>
-<!ATTLIST member name CDATA #REQUIRED>
-
-<!ELEMENT interface (method*)>
-<!ATTLIST interface name CDATA #REQUIRED>
-<!ATTLIST interface manual_name CDATA #IMPLIED>
-<!ATTLIST interface cap_description CDATA #IMPLIED>
-
-<!ELEMENT method (brief?,description?,return?,cap_param?,param*,error*)>
-<!ATTLIST method name CDATA #REQUIRED>
-<!ATTLIST method id CDATA #REQUIRED>
-<!ATTLIST method condition CDATA #IMPLIED>
-<!ATTLIST method manual_name CDATA #IMPLIED>
-<!ATTLIST method manual_label CDATA #IMPLIED>
-
-<!ELEMENT param (description?, error*)>
-<!ATTLIST param type CDATA #REQUIRED>
-<!ATTLIST param name CDATA #REQUIRED>
-<!ATTLIST param dir CDATA #REQUIRED>
-<!ATTLIST param description CDATA #IMPLIED>
-
-<!ELEMENT error (description?)>
-<!ATTLIST error name CDATA #REQUIRED>
-<!ATTLIST error description CDATA #IMPLIED>
-
-<!ELEMENT brief (#PCDATA|texttt|docref|shortref|autoref|obj)*>
-
-<!ELEMENT description (#PCDATA|texttt|docref|shortref|autoref|obj)*>
-
-<!ELEMENT return (#PCDATA|texttt|docref|shortref|autoref|obj|errorenumdesc)*>
-
-<!ELEMENT docref (#PCDATA|texttt|shortref|autoref|obj)*>
-
-<!ELEMENT texttt EMPTY>
-<!ATTLIST texttt text CDATA #REQUIRED>
-
-<!ELEMENT autoref EMPTY>
-<!ATTLIST autoref label CDATA #REQUIRED>
-
-<!ELEMENT shortref EMPTY>
-<!ATTLIST shortref sec CDATA #REQUIRED>
-
-<!ELEMENT obj EMPTY>
-<!ATTLIST obj name CDATA #REQUIRED>
-
-<!ELEMENT errorenumdesc EMPTY>
-
-<!ELEMENT cap_param EMPTY>
-<!ATTLIST cap_param append_description CDATA #IMPLIED>
diff --git a/libsel4/tools/sel4_idl.xsd b/libsel4/tools/sel4_idl.xsd
new file mode 100644
index 000000000..b8d71f720
--- /dev/null
+++ b/libsel4/tools/sel4_idl.xsd
@@ -0,0 +1,138 @@
+<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
+<!--
+     Copyright 2022, seL4 Project a Series of LF Projects, LLC
+
+     SPDX-License-Identifier: BSD-2-Clause
+-->
+
+    <xsd:annotation>
+        <xsd:documentation xml:lang="en">
+            seL4 api generator schema.
+        </xsd:documentation>
+    </xsd:annotation>
+
+    <xsd:element name="api" type="APIType"/>
+
+    <xsd:complexType name="APIType">
+        <xsd:sequence>
+            <xsd:element name="struct" minOccurs="0" maxOccurs="unbounded" type="StructType" />
+            <xsd:element name="interface" minOccurs="0" maxOccurs="unbounded" type="InterfaceType"/>
+        </xsd:sequence>
+        <xsd:attribute name="name" type="xsd:string" use="optional" />
+        <xsd:attribute name="label_prefix" type="xsd:string" use="optional"/>
+    </xsd:complexType>
+
+    <xsd:complexType name="StructType">
+        <xsd:sequence>
+            <xsd:element name="member" minOccurs="0" maxOccurs="unbounded" type="StructMemberType" />
+        </xsd:sequence>
+        <xsd:attribute name="name" type="xsd:string" use="required" />
+    </xsd:complexType>
+
+    <xsd:complexType name="StructMemberType">
+        <xsd:attribute name="name" type="xsd:string" use="required" />
+    </xsd:complexType>
+
+    <xsd:complexType name="InterfaceType">
+        <xsd:sequence>
+            <xsd:element name="method" minOccurs="0" maxOccurs="unbounded" type="MethodType"/>
+        </xsd:sequence>
+        <xsd:attribute name="name" type="xsd:string" use="required" />
+        <xsd:attribute name="manual_name" type="xsd:string" use="optional" />
+        <xsd:attribute name="cap_description" type="xsd:string" use="optional" />
+    </xsd:complexType>
+
+
+    <xsd:complexType name="MethodType">
+        <xsd:sequence>
+            <xsd:element name="brief" type="DescriptionType" minOccurs="0" maxOccurs="1" />
+            <xsd:element name="description" type="DescriptionType" minOccurs="0" maxOccurs="1" />
+            <xsd:element name="return" type="ReturnType" minOccurs="0" maxOccurs="1" />
+            <xsd:element name="cap_param" type="CapParamType" minOccurs="0" maxOccurs="1" />
+            <xsd:element name="param" type="ParamType" minOccurs="0" maxOccurs="unbounded" />
+            <xsd:element name="error" type="ErrorType" minOccurs="0" maxOccurs="unbounded" />
+        </xsd:sequence>
+        <xsd:attribute name="name" type="xsd:string" use="required" />
+        <xsd:attribute name="id" type="xsd:string" use="required" />
+        <xsd:attribute name="condition" type="xsd:string" use="optional" />
+        <xsd:attribute name="manual_name" type="xsd:string" use="optional" />
+        <xsd:attribute name="manual_label" type="xsd:string" use="optional" />
+    </xsd:complexType>
+
+    <xsd:group name="DocElements">
+        <xsd:choice>
+            <xsd:element name="texttt">
+                <xsd:complexType>
+                <xsd:simpleContent>
+                    <xsd:extension base="xsd:string">
+                        <xsd:attribute name="text" type="xsd:string"/>
+                    </xsd:extension>
+                </xsd:simpleContent>
+                </xsd:complexType>
+            </xsd:element>
+            <xsd:element name="shortref" type="ShortRefType"/>
+            <xsd:element name="obj" type="ObjType"/>
+            <xsd:element name="autoref" type="AutoRefType"/>
+        </xsd:choice>
+    </xsd:group>
+
+
+    <xsd:complexType name="DescriptionType" mixed="true">
+        <xsd:choice minOccurs="0" maxOccurs="unbounded">
+            <xsd:group ref="DocElements" minOccurs="0" maxOccurs="unbounded"/>
+            <xsd:element name="docref" type="DocRefType"/>
+        </xsd:choice>
+    </xsd:complexType>
+
+    <xsd:complexType name="ReturnType" mixed="true">
+        <xsd:choice minOccurs="0" maxOccurs="unbounded">
+            <xsd:group ref="DocElements" minOccurs="0" maxOccurs="unbounded"/>
+            <xsd:element name="docref" type="DocRefType"/>
+            <xsd:element name="errorenumdesc" type="ErrorEnumDescType"/>
+        </xsd:choice>
+    </xsd:complexType>
+
+    <xsd:complexType name="DocRefType" mixed="true">
+        <xsd:choice minOccurs="0" maxOccurs="unbounded">
+            <xsd:group ref="DocElements" minOccurs="0" maxOccurs="unbounded"/>
+        </xsd:choice>
+    </xsd:complexType>
+
+    <xsd:complexType name="CapParamType">
+        <xsd:attribute name="append_description" type="xsd:string" use="optional"/>
+    </xsd:complexType>
+
+    <xsd:complexType name="ParamType">
+        <xsd:sequence>
+            <xsd:element name="description" minOccurs="0" maxOccurs="1" type="DescriptionType"/>
+            <xsd:element name="error" minOccurs="0" maxOccurs="unbounded" type="ErrorType"/>
+        </xsd:sequence>
+        <xsd:attribute name="type" type="xsd:string" use="required"/>
+        <xsd:attribute name="name" type="xsd:string" use="required"/>
+        <xsd:attribute name="dir" type="xsd:string" use="required"/>
+        <xsd:attribute name="description" type="xsd:string" use="optional"/>
+    </xsd:complexType>
+
+    <xsd:complexType name="ErrorType">
+        <xsd:choice>
+            <xsd:element name="description" type="DescriptionType" minOccurs="0" maxOccurs="1"/>
+        </xsd:choice>
+        <xsd:attribute name="name" type="xsd:string" use="required"/>
+        <xsd:attribute name="description" type="xsd:string" use="optional"/>
+    </xsd:complexType>
+
+    <xsd:complexType name="ShortRefType">
+        <xsd:attribute name="sec" type="xsd:string" use="required"/>
+    </xsd:complexType>
+
+    <xsd:complexType name="AutoRefType">
+        <xsd:attribute name="label" type="xsd:string" use="required"/>
+    </xsd:complexType>
+
+
+    <xsd:complexType name="ObjType">
+        <xsd:attribute name="name" type="xsd:string" use="required"/>
+    </xsd:complexType>
+
+    <xsd:complexType name="ErrorEnumDescType"/>
+</xsd:schema>
diff --git a/manual/Makefile b/manual/Makefile
index 1b86009d1..77f946356 100644
--- a/manual/Makefile
+++ b/manual/Makefile
@@ -86,7 +86,7 @@ GenerationTool = tools/parse_doxygen_xml.py
 
 GenerateObjectInvocationTool = tools/gen_invocations.py
 
-InterfaceDtd = $(Libsel4Dir)/tools/sel4_idl.dtd
+InterfaceDtd = $(Libsel4Dir)/tools/sel4_idl.xsd
 
 .PHONY: FORCE
 
diff --git a/manual/tools/gen_invocations.py b/manual/tools/gen_invocations.py
index d629130c8..ad0731019 100755
--- a/manual/tools/gen_invocations.py
+++ b/manual/tools/gen_invocations.py
@@ -123,7 +123,7 @@ def main():
     args = parser.parse_args()
 
     if args.dtd is not None:
-        dtd = etree.DTD(args.dtd)
+        dtd = etree.XMLSchema(etree.parse(args.dtd))
         for f in args.files:
             xml = etree.parse(f)
             if not dtd.validate(xml):