diff --git a/.changeset/twelve-chairs-drop.md b/.changeset/twelve-chairs-drop.md
new file mode 100644
index 000000000..de9e807d9
--- /dev/null
+++ b/.changeset/twelve-chairs-drop.md
@@ -0,0 +1,5 @@
+---
+'graphql-scalars': minor
+---
+
+Add new Swedish Personal Number scalar
diff --git a/src/index.ts b/src/index.ts
index 0f9ae6c97..77806dac2 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -57,6 +57,7 @@ import {
   GraphQLRoutingNumber,
   GraphQLSafeInt,
   GraphQLSemVer,
+  GraphQLSESSN,
   GraphQLTime,
   GraphQLTimestamp,
   GraphQLTimeZone,
@@ -132,6 +133,7 @@ export {
   AccountNumber as AccountNumberDefinition,
   Cuid as CuidDefinition,
   SemVer as SemVerDefinition,
+  SemVer as SESSNDefinition,
   DeweyDecimal as DeweyDecimalDefinition,
   LCCSubclass as LCCSubclassDefinition,
   IPCPatent as IPCPatentDefinition,
@@ -203,6 +205,7 @@ export {
   GraphQLAccountNumber as AccountNumberResolver,
   GraphQLCuid as CuidResolver,
   GraphQLSemVer as SemVerResolver,
+  GraphQLSESSN as SESSNResolver,
   GraphQLDeweyDecimal as GraphQLDeweyDecimalResolver,
   GraphQLIPCPatent as GraphQLIPCPatentResolver,
 };
@@ -271,6 +274,7 @@ export const resolvers: Record<string, GraphQLScalarType> = {
   AccountNumber: GraphQLAccountNumber,
   Cuid: GraphQLCuid,
   SemVer: GraphQLSemVer,
+  SESSN: GraphQLSESSN,
   DeweyDecimal: GraphQLDeweyDecimal,
   LCCSubclass: GraphQLLCCSubclass,
   IPCPatent: GraphQLIPCPatent,
@@ -340,6 +344,7 @@ export {
   AccountNumber as AccountNumberMock,
   Cuid as CuidMock,
   SemVer as SemVerMock,
+  SESSN as SESSNMock,
   DeweyDecimal as DeweyDecimalMock,
   LCCSubclass as LCCSubclassMock,
   IPCPatent as IPCPatentMock,
@@ -417,6 +422,7 @@ export {
   GraphQLAccountNumber,
   GraphQLCuid,
   GraphQLSemVer,
+  GraphQLSESSN,
   GraphQLDeweyDecimal,
   GraphQLLCCSubclass,
   GraphQLIPCPatent,
diff --git a/src/mocks.ts b/src/mocks.ts
index 1b24236de..c898ef31d 100644
--- a/src/mocks.ts
+++ b/src/mocks.ts
@@ -111,6 +111,7 @@ export const RoutingNumber = () => '111000025';
 export const AccountNumber = () => '000000012345';
 export const Cuid = () => 'cjld2cyuq0000t3rmniod1foy';
 export const SemVer = () => '1.0.0-alpha.1';
+export const SESSN = () => '194907011813';
 export const DeweyDecimal = () => '435.4357';
 export const LCCSubclass = () => 'KBM';
 export const IPCPatent = () => 'G06F 12/803';
diff --git a/src/scalars/index.ts b/src/scalars/index.ts
index b69274934..486e35b92 100644
--- a/src/scalars/index.ts
+++ b/src/scalars/index.ts
@@ -61,6 +61,7 @@ export { GraphQLRoutingNumber } from './RoutingNumber.js';
 export { GraphQLAccountNumber } from './AccountNumber.js';
 export { GraphQLCuid } from './Cuid.js';
 export { GraphQLSemVer } from './SemVer.js';
+export { GraphQLSESSN } from './ssn/SE.js';
 export { GraphQLDeweyDecimal } from './library/DeweyDecimal.js';
 export { GraphQLLCCSubclass } from './library/LCCSubclass.js';
 export { GraphQLIPCPatent } from './patent/IPCPatent.js';
diff --git a/src/scalars/ssn/SE.ts b/src/scalars/ssn/SE.ts
new file mode 100644
index 000000000..3fbf6cd1a
--- /dev/null
+++ b/src/scalars/ssn/SE.ts
@@ -0,0 +1,138 @@
+import { GraphQLScalarType, Kind } from 'graphql';
+import { createGraphQLError } from '../../error.js';
+
+// Swedish Personal Number also known as 'personnummer' in swedish:
+// https://www.skatteverket.se/privat/folkbokforing/personnummer.4.3810a01c150939e893f18c29.html
+// Algorithm:
+// https://swedish.identityinfo.net/personalidentitynumber
+
+const SESSN_PATTERNS = ['YYYYMMDDXXXX', 'YYMMDDXXXX'];
+
+function _isValidSwedishPersonalNumber(value: string): boolean {
+  // Remove any non-digit characters
+  const pno: string = value.replace(/\D/g, '');
+  // Check if the cleaned number has the correct length (10 or 12 digits)
+  if (pno.length !== 10 && pno.length !== 12) {
+    return false;
+  }
+
+  // Validate the birthdate
+  if (!_isValidDate(pno)) {
+    return false;
+  }
+
+  // Check the checksum for numbers
+  if (!_isValidChecksum(pno)) {
+    return false;
+  }
+
+  // If all checks pass, the personal number is valid
+  return true;
+}
+
+function _isValidDate(pno: string): boolean {
+  let year: number;
+  let month: number;
+  let day: number;
+
+  if (pno.length === 10) {
+    year = Number(pno.substring(0, 2));
+    // Adjust the input 'year' to a four-digit year based on the assumption that two-digit years greater than the current year are in the past century (1900s),
+    // while two-digit years less than or equal to the current year are in the current or upcoming century (2000s).
+    year = year > Number(String(new Date().getFullYear()).substring(2)) ? 1900 + year : 2000 + year;
+    month = Number(pno.substring(2, 4));
+    day = Number(pno.substring(4, 6));
+  } else {
+    year = Number(pno.substring(0, 4));
+    month = Number(pno.substring(4, 6));
+    day = Number(pno.substring(6, 8));
+  }
+
+  const date = new Date(year, month - 1, day);
+
+  return date.getFullYear() === year && date.getMonth() + 1 === month && date.getDate() === day;
+}
+
+function _isValidChecksum(pno: string): boolean {
+  const shortPno: string = pno.length === 12 ? pno.substring(2, 12) : pno;
+  const digits: number[] = shortPno.split('').map(Number);
+  let sum: number = 0;
+
+  for (let i: number = 0; i < digits.length; i++) {
+    let digit = digits[i];
+
+    // Double every second digit from the right
+    if (i % 2 === digits.length % 2) {
+      digit *= 2;
+      if (digit > 9) {
+        digit -= 9;
+      }
+    }
+
+    sum += digit;
+  }
+
+  // Check if the sum is a multiple of 10
+  return sum % 10 === 0;
+}
+
+function _checkString(value: any): void {
+  if (typeof value !== 'string') {
+    throw createGraphQLError(`Value is not string: ${value}`);
+  }
+}
+
+function _checkSSN(value: string): void {
+  if (!_isValidSwedishPersonalNumber(value)) {
+    throw createGraphQLError(`Value is not a valid swedish personal number: ${value}`);
+  }
+}
+
+export const GraphQLSESSN: GraphQLScalarType = /*#__PURE__*/ new GraphQLScalarType({
+  name: 'SESSN',
+  description:
+    'A field whose value conforms to the standard personal number (personnummer) formats for Sweden',
+
+  serialize(value) {
+    _checkString(value);
+    _checkSSN(value as string);
+
+    return value;
+  },
+
+  parseValue(value) {
+    _checkString(value);
+    _checkSSN(value as string);
+
+    return value;
+  },
+
+  parseLiteral(ast) {
+    if (ast.kind !== Kind.STRING) {
+      throw createGraphQLError(
+        `Can only validate strings as swedish personal number but got a: ${ast.kind}`,
+        { nodes: ast },
+      );
+    }
+
+    if (!_isValidSwedishPersonalNumber(ast.value)) {
+      throw createGraphQLError(`Value is not a valid swedish personal number: ${ast.value}`, {
+        nodes: ast,
+      });
+    }
+
+    return ast.value;
+  },
+
+  extensions: {
+    codegenScalarType: 'string',
+    jsonSchema: {
+      title: 'SESSN',
+      oneOf: SESSN_PATTERNS.map((pattern: string) => ({
+        type: 'string',
+        length: pattern.length,
+        pattern,
+      })),
+    },
+  },
+});
diff --git a/src/typeDefs.ts b/src/typeDefs.ts
index 0fcc6dd44..103e66495 100644
--- a/src/typeDefs.ts
+++ b/src/typeDefs.ts
@@ -52,6 +52,7 @@ export const RoutingNumber = 'scalar RoutingNumber';
 export const AccountNumber = 'scalar AccountNumber';
 export const Cuid = 'scalar Cuid';
 export const SemVer = 'scalar SemVer';
+export const SESSN = 'scalar SESSN';
 
 export const UnsignedFloat = 'scalar UnsignedFloat';
 export const UnsignedInt = 'scalar UnsignedInt';
@@ -133,6 +134,7 @@ export const typeDefs = [
   AccountNumber,
   Cuid,
   SemVer,
+  SESSN,
   DeweyDecimal,
   LCCSubclass,
   IPCPatent,
diff --git a/tests/ssn/SE.test.ts b/tests/ssn/SE.test.ts
new file mode 100644
index 000000000..06e187c0a
--- /dev/null
+++ b/tests/ssn/SE.test.ts
@@ -0,0 +1,101 @@
+import { Kind } from 'graphql/language';
+import { GraphQLSESSN } from '../../src/scalars/ssn/SE.js';
+
+// List was taken from https://www.uc.se/developer/consumer-reports/getting-started/
+// and https://skatteverket.entryscape.net/catalog/9/datasets/147
+const SSNs = [
+  '194907011813',
+  '4907011813',
+  '194006128989',
+  '4006128989',
+  '196512233666',
+  '193303190718',
+  '3303190718',
+  '195207199398',
+  '5207199398',
+];
+
+describe(`SSN => SE`, () => {
+  describe(`valid`, () => {
+    it(`serialize`, () => {
+      for (const value of SSNs) {
+        expect(GraphQLSESSN.serialize(value)).toEqual(value);
+      }
+    });
+
+    it(`parseValue`, () => {
+      for (const value of SSNs) {
+        expect(GraphQLSESSN.parseValue(value)).toEqual(value);
+      }
+    });
+
+    it(`parseLiteral`, () => {
+      for (const value of SSNs) {
+        expect(
+          GraphQLSESSN.parseLiteral(
+            {
+              value,
+              kind: Kind.STRING,
+            },
+            {},
+          ),
+        ).toEqual(value);
+      }
+    });
+  });
+
+  describe(`invalid`, () => {
+    describe(`not a valid swedish personal number`, () => {
+      it(`serialize`, () => {
+        expect(() => GraphQLSESSN.serialize(123456789012)).toThrow(/Value is not string/);
+        expect(() => GraphQLSESSN.serialize(`this is not a swedish personal number`)).toThrow(
+          /Value is not a valid swedish personal number: this is not a swedish personal number/,
+        );
+        expect(() => GraphQLSESSN.serialize(`123456789012`)).toThrow(
+          /Value is not a valid swedish personal number: 123456789012/,
+        );
+        expect(() => GraphQLSESSN.serialize(`194907011811`)).toThrow(
+          /Value is not a valid swedish personal number: 194907011811/,
+        );
+        expect(() => GraphQLSESSN.serialize(`4907011811`)).toThrow(
+          /Value is not a valid swedish personal number: 4907011811/,
+        );
+      });
+
+      it(`parseValue`, () => {
+        expect(() => GraphQLSESSN.serialize(123456789012)).toThrow(/Value is not string/);
+        expect(() => GraphQLSESSN.parseValue(`this is not a swedish personal number`)).toThrow(
+          /Value is not a valid/,
+        );
+        expect(() => GraphQLSESSN.parseValue(`123456789012`)).toThrow(
+          /Value is not a valid swedish personal number: 123456789012/,
+        );
+        expect(() => GraphQLSESSN.serialize(`194907011811`)).toThrow(
+          /Value is not a valid swedish personal number: 194907011811/,
+        );
+        expect(() => GraphQLSESSN.serialize(`4907011811`)).toThrow(
+          /Value is not a valid swedish personal number: 4907011811/,
+        );
+      });
+
+      it(`parseLiteral`, () => {
+        expect(() =>
+          GraphQLSESSN.parseLiteral({ value: 123456789012, kind: Kind.INT } as any, {}),
+        ).toThrow(/Can only validate strings as swedish personal number but got a: IntValue/);
+
+        expect(() =>
+          GraphQLSESSN.parseLiteral({ value: `123456789012`, kind: Kind.INT } as any, {}),
+        ).toThrow(/Can only validate strings as swedish personal number but got a: IntValue/);
+
+        expect(() =>
+          GraphQLSESSN.parseLiteral(
+            { value: `this is not a swedish personal number`, kind: Kind.STRING },
+            {},
+          ),
+        ).toThrow(
+          /Value is not a valid swedish personal number: this is not a swedish personal number/,
+        );
+      });
+    });
+  });
+});
diff --git a/website/src/pages/docs/scalars/ssn.mdx b/website/src/pages/docs/scalars/ssn.mdx
new file mode 100644
index 000000000..0924e40ba
--- /dev/null
+++ b/website/src/pages/docs/scalars/ssn.mdx
@@ -0,0 +1,15 @@
+# SSN
+
+## SE (Swedish Personal Number `personnummer`)
+
+Accepts the value in the following formats:
+
+- YYYYMMDDXXXX
+- YYMMDDXXXX
+
+In case of 10 digit format, it adjusts the 'year' to a four-digit year based on the assumption that
+two-digit years greater than the current year are in the past century (1900s), while two-digit years
+less than or equal to the current year are in the current or upcoming century (2000s).
+
+Reference:
+https://www.skatteverket.se/privat/folkbokforing/personnummer.4.3810a01c150939e893f18c29.html