diff --git a/src/Microsoft.IdentityModel.JsonWebTokens/Json/JsonClaimSet.cs b/src/Microsoft.IdentityModel.JsonWebTokens/Json/JsonClaimSet.cs
index 914c33768b..b9868dd9e7 100644
--- a/src/Microsoft.IdentityModel.JsonWebTokens/Json/JsonClaimSet.cs
+++ b/src/Microsoft.IdentityModel.JsonWebTokens/Json/JsonClaimSet.cs
@@ -61,7 +61,13 @@ internal static void CreateClaimFromObject(List<Claim> claims, string claimType,
             else if (value is long l)
                 claims.Add(new Claim(claimType, l.ToString(CultureInfo.InvariantCulture), ClaimValueTypes.Integer64, issuer, issuer));
             else if (value is bool b)
-                claims.Add(new Claim(claimType, b.ToString(CultureInfo.InvariantCulture), ClaimValueTypes.Boolean, issuer, issuer));
+            {
+                // Can't just use ToString or bools will get encoded as True/False instead of true/false.
+                if (b)
+                    claims.Add(new Claim(claimType, "true", ClaimValueTypes.Boolean, issuer, issuer));
+                else
+                    claims.Add(new Claim(claimType, "false", ClaimValueTypes.Boolean, issuer, issuer));
+            }
             else if (value is double d)
                 claims.Add(new Claim(claimType, d.ToString(CultureInfo.InvariantCulture), ClaimValueTypes.Double, issuer, issuer));
             else if (value is DateTime dt)
@@ -108,9 +114,9 @@ internal static Claim CreateClaimFromJsonElement(string claimType, string issuer
             else if (jsonElement.ValueKind == JsonValueKind.Object)
                 return new Claim(claimType, jsonElement.ToString(), JsonClaimValueTypes.Json, issuer, issuer);
             else if (jsonElement.ValueKind == JsonValueKind.False)
-                return new Claim(claimType, "False", ClaimValueTypes.Boolean, issuer, issuer);
+                return new Claim(claimType, "false", ClaimValueTypes.Boolean, issuer, issuer);
             else if (jsonElement.ValueKind == JsonValueKind.True)
-                return new Claim(claimType, "True", ClaimValueTypes.Boolean, issuer, issuer);
+                return new Claim(claimType, "true", ClaimValueTypes.Boolean, issuer, issuer);
             else if (jsonElement.ValueKind == JsonValueKind.Number)
             {
                 if (jsonElement.TryGetInt32(out int i))
diff --git a/src/System.IdentityModel.Tokens.Jwt/JwtPayload.cs b/src/System.IdentityModel.Tokens.Jwt/JwtPayload.cs
index 32efc9e3e1..d89bf96874 100644
--- a/src/System.IdentityModel.Tokens.Jwt/JwtPayload.cs
+++ b/src/System.IdentityModel.Tokens.Jwt/JwtPayload.cs
@@ -543,6 +543,14 @@ public virtual IEnumerable<Claim> Claims
                     }
                     else if (keyValuePair.Value is DateTime dateTime)
                         claims.Add(new Claim(keyValuePair.Key, dateTime.ToString("o", CultureInfo.InvariantCulture), ClaimValueTypes.DateTime, issuer, issuer));
+                    else if (keyValuePair.Value is bool boolValue)
+                    {
+                        // Can't just use ToString or bools will get encoded as True/False instead of true/false.
+                        if (boolValue)
+                            claims.Add(new Claim(keyValuePair.Key, "true", ClaimValueTypes.Boolean, issuer, issuer));
+                        else
+                            claims.Add(new Claim(keyValuePair.Key, "false", ClaimValueTypes.Boolean, issuer, issuer));
+                    }
                     else if (keyValuePair.Value != null)
                         claims.Add(new Claim(keyValuePair.Key, keyValuePair.Value.ToString(), GetClaimValueType(keyValuePair.Value), issuer, issuer));
                 }
@@ -557,6 +565,13 @@ private void AddListofObjects(string key, IEnumerable<object> objects, List<Clai
             {
                 if (obj is string claimValue)
                     claims.Add(new Claim(key, claimValue, ClaimValueTypes.String, issuer, issuer));
+                else if (obj is bool boolValue)
+                {
+                    if (boolValue)
+                        claims.Add(new Claim(key, "true", ClaimValueTypes.Boolean, issuer, issuer));
+                    else
+                        claims.Add(new Claim(key, "false", ClaimValueTypes.Boolean, issuer, issuer));
+                }
                 else if (obj is DateTime dateTimeValue)
                     claims.Add(new Claim(key, dateTimeValue.ToString("o", CultureInfo.InvariantCulture), ClaimValueTypes.DateTime, issuer, issuer));
                 else if (obj is JsonElement jsonElement)
diff --git a/test/Microsoft.IdentityModel.JsonWebTokens.Tests/JsonWebTokenTests.cs b/test/Microsoft.IdentityModel.JsonWebTokens.Tests/JsonWebTokenTests.cs
index 600949834b..a20ef8c3ef 100644
--- a/test/Microsoft.IdentityModel.JsonWebTokens.Tests/JsonWebTokenTests.cs
+++ b/test/Microsoft.IdentityModel.JsonWebTokens.Tests/JsonWebTokenTests.cs
@@ -37,11 +37,39 @@ public class JsonWebTokenTests
             new Claim("float", "42", ClaimValueTypes.Integer32, "LOCAL AUTHORITY", "LOCAL AUTHORITY"),
             new Claim("integer", "42", ClaimValueTypes.Integer32, "LOCAL AUTHORITY", "LOCAL AUTHORITY"),
             new Claim("nill", "", JsonClaimValueTypes.JsonNull, "LOCAL AUTHORITY", "LOCAL AUTHORITY"),
-            new Claim("bool", "True", ClaimValueTypes.Boolean, "LOCAL AUTHORITY", "LOCAL AUTHORITY"),
+            new Claim("bool", "true", ClaimValueTypes.Boolean, "LOCAL AUTHORITY", "LOCAL AUTHORITY"),
             new Claim("dateTime", dateTime.ToString(), ClaimValueTypes.String, "LOCAL AUTHORITY", "LOCAL AUTHORITY"),
             new Claim("dateTimeIso8061", dateTime.ToUniversalTime().ToString("o", CultureInfo.InvariantCulture), ClaimValueTypes.DateTime, "LOCAL AUTHORITY", "LOCAL AUTHORITY"),
         };
 
+        [Fact]
+        public void BoolClaimsEncodedAsExpected()
+        {
+            var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(new string('a', 128)));
+            var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+            var claims = new[] { new Claim("testClaim", "true", ClaimValueTypes.Boolean), new Claim("testClaim2", "True", ClaimValueTypes.Boolean) };
+            SecurityTokenDescriptor tokenDescriptor = new SecurityTokenDescriptor
+            {
+                SigningCredentials = creds,
+                Subject = new ClaimsIdentity(claims),
+                Expires = (new DateTime(2038, 1, 20)).ToUniversalTime(),
+            };
+
+            JsonWebTokenHandler handler = new();
+            string jwt = handler.CreateToken(tokenDescriptor);
+            JsonWebToken jsonWebToken = new JsonWebToken(jwt);
+
+            var claimSet = jsonWebToken.Claims;
+
+            // Will throw if can't find.
+            var testClaim = claimSet.First(c => c.Type == "testClaim");
+            Assert.Equal("true", testClaim.Value);
+
+            var testClaim2 = claimSet.First(c => c.Type == "testClaim2");
+            Assert.Equal("true", testClaim2.Value);
+        }
+
         [Fact]
         public void DateTime2038Issue()
         {
diff --git a/test/System.IdentityModel.Tokens.Jwt.Tests/JwtPayloadTest.cs b/test/System.IdentityModel.Tokens.Jwt.Tests/JwtPayloadTest.cs
index 90b5f3a5e1..9798607dc5 100644
--- a/test/System.IdentityModel.Tokens.Jwt.Tests/JwtPayloadTest.cs
+++ b/test/System.IdentityModel.Tokens.Jwt.Tests/JwtPayloadTest.cs
@@ -256,8 +256,8 @@ public static TheoryData<string, List<Claim>, JwtPayload, JwtPayload> PayloadDat
                     new List<Claim>
                     {
                         new Claim("ClaimValueTypes.String", "ClaimValueTypes.String.Value", ClaimValueTypes.String),
-                        new Claim("ClaimValueTypes.Boolean.true", "True", ClaimValueTypes.Boolean),
-                        new Claim("ClaimValueTypes.Boolean.false", "False", ClaimValueTypes.Boolean),
+                        new Claim("ClaimValueTypes.Boolean.true", "true", ClaimValueTypes.Boolean),
+                        new Claim("ClaimValueTypes.Boolean.false", "false", ClaimValueTypes.Boolean),
                         new Claim("ClaimValueTypes.Double", "123.4", ClaimValueTypes.Double),
                         new Claim("ClaimValueTypes.int.MaxValue", intMaxValue, ClaimValueTypes.Integer32),
                         new Claim("ClaimValueTypes.int.MinValue", intMinValue, ClaimValueTypes.Integer32),
@@ -300,8 +300,8 @@ public static TheoryData<string, List<Claim>, JwtPayload, JwtPayload> PayloadDat
                         new Claim("ClaimValueTypes", longValue, ClaimValueTypes.Integer64),
                         new Claim("ClaimValueTypes", "132.64", ClaimValueTypes.Double),
                         new Claim("ClaimValueTypes", "-132.64", ClaimValueTypes.Double),
-                        new Claim("ClaimValueTypes", "True", ClaimValueTypes.Boolean),
-                        new Claim("ClaimValueTypes", "False", ClaimValueTypes.Boolean),
+                        new Claim("ClaimValueTypes", "true", ClaimValueTypes.Boolean),
+                        new Claim("ClaimValueTypes", "false", ClaimValueTypes.Boolean),
                         new Claim("ClaimValueTypes", "2019-11-15T14:31:21.6101326Z", ClaimValueTypes.DateTime),
                         new Claim("ClaimValueTypes", "2019-11-15", ClaimValueTypes.String),
                         new Claim("ClaimValueTypes", @"{""name3.1"":""value3.1""}", JsonClaimValueTypes.Json),
diff --git a/test/System.IdentityModel.Tokens.Jwt.Tests/JwtSecurityTokenTests.cs b/test/System.IdentityModel.Tokens.Jwt.Tests/JwtSecurityTokenTests.cs
index 629fb694df..c53fcb5144 100644
--- a/test/System.IdentityModel.Tokens.Jwt.Tests/JwtSecurityTokenTests.cs
+++ b/test/System.IdentityModel.Tokens.Jwt.Tests/JwtSecurityTokenTests.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System.Collections.Generic;
+using System.Linq;
 using System.Security.Claims;
 using System.Text;
 using Microsoft.IdentityModel.Logging;
@@ -13,6 +14,30 @@ namespace System.IdentityModel.Tokens.Jwt.Tests
 {
     public class JwtSecurityTokenTests
     {
+        [Fact]
+        public void BoolClaimsEncodedAsExpected()
+        {
+            var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(new string('a', 128)));
+            var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+            var claims = new[] { new Claim("testClaim", "true", ClaimValueTypes.Boolean), new Claim("testClaim2", "True", ClaimValueTypes.Boolean) };
+            var token = new JwtSecurityToken(
+                issuer: "issuer.contoso.com",
+                audience: "audience.contoso.com",
+                claims: claims,
+                expires: (new DateTime(2038, 1, 20)).ToUniversalTime(),
+                signingCredentials: creds);
+
+            var claimSet = token.Claims;
+
+            // Will throw if can't find.
+            var testClaim = claimSet.First(c => c.Type == "testClaim");
+            Assert.Equal("true", testClaim.Value);
+
+            var testClaim2 = claimSet.First(c => c.Type == "testClaim2");
+            Assert.Equal("true", testClaim2.Value);
+        }
+
         [Fact]
         public void DateTime2038Issue()
         {