diff --git a/lotman/lotman_linux.go b/lotman/lotman_linux.go
index 8feabcec1..932babcf5 100644
--- a/lotman/lotman_linux.go
+++ b/lotman/lotman_linux.go
@@ -28,6 +28,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"reflect"
 	"runtime"
 	"strconv"
 	"strings"
@@ -37,6 +38,7 @@ import (
 	"unsafe"
 
 	"github.com/ebitengine/purego"
+	"github.com/mitchellh/mapstructure"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
@@ -77,7 +79,7 @@ var (
 
 type (
 	Int64FromFloat struct {
-		Value int64
+		Value int64 `mapstructure:"Value"`
 	}
 
 	LotPath struct {
@@ -170,12 +172,12 @@ type (
 	}
 
 	PurgePolicy struct {
-		PurgeOrder               []string `json:"purge_order"`
-		PolicyName               string   `json:"policy_name"`
-		DiscoverPrefixes         bool     `json:"discover_prefixes"`
-		MergeLocalWithDiscovered bool     `json:"merge_local_with_discovered"`
-		DivideUnallocated        bool	  `json:"divide_unallocated"`
-		Lots                     []Lot    `json:"lots"`
+		PurgeOrder               []string `mapstructure:"PurgeOrder"`
+		PolicyName               string   `mapstructure:"PolicyName"`
+		DiscoverPrefixes         bool     `mapstructure:"DiscoverPrefixes"`
+		MergeLocalWithDiscovered bool     `mapstructure:"MergeLocalWithDiscovered"`
+		DivideUnallocated        bool     `mapstructure:"DivideUnallocated"`
+		Lots                     []Lot    `mapstructure:"Lots"`
 	}
 )
 
@@ -428,13 +430,40 @@ func mergeLotMaps(map1, map2 map[string]Lot) (map[string]Lot, error) {
     return result, nil
 }
 
+// A hook function for mapstructure that validates that all fields in the map are present in the struct.
+// Used to verify the user's input for PolicyDefinitions, since these aren't top-level fields in parameters.yaml
+func validateFieldsHook() mapstructure.DecodeHookFunc {
+    return func(from reflect.Type, to reflect.Type, data interface{}) (interface{}, error) {
+        if from.Kind() != reflect.Map || to.Kind() != reflect.Struct {
+            return data, nil
+        }
+
+        mapKeys := reflect.ValueOf(data).MapKeys()
+        structFields := make(map[string]struct{})
+        for i := 0; i < to.NumField(); i++ {
+            field := to.Field(i)
+            // Normalize the field name to lowercase
+            structFields[strings.ToLower(field.Tag.Get("mapstructure"))] = struct{}{}
+        }
+
+        // Check for unknown fields
+        for _, key := range mapKeys {
+            if _, ok := structFields[strings.ToLower(key.String())]; !ok {
+                return nil, fmt.Errorf("unknown configuration field in Lotman policy definitions: %s", key.String())
+            }
+        }
+
+        return data, nil
+    }
+}
+
 // Grab a map of policy definitions from the config file, where the policy
 // name is the key and its attributes comprise the value.
 func getPolicyMap() (map[string]PurgePolicy, error) {
 	policyMap := make(map[string]PurgePolicy)
 	var policies []PurgePolicy
-	err := viper.UnmarshalKey("Lotman.PolicyDefinitions", &policies)
-	if err != nil {
+	// Use custom decoder hook to validate fields. This validates all the way down to the bottom of the lot object.
+	if err := viper.UnmarshalKey(param.Lotman_PolicyDefinitions.GetName(), &policies, viper.DecodeHook(validateFieldsHook())); err != nil {
 		return policyMap, errors.Wrap(err, "error unmarshaling Lotman policy definitions")
 	}
 
diff --git a/lotman/lotman_test.go b/lotman/lotman_test.go
index a03f47917..d872d4b02 100644
--- a/lotman/lotman_test.go
+++ b/lotman/lotman_test.go
@@ -47,6 +47,9 @@ import (
 //go:embed resources/lots-config.yaml
 var yamlMockup string
 
+//go:embed resources/malformed-lots-config.yaml
+var badYamlMockup string
+
 // Helper function for determining policy index from lot config yaml
 func findPolicyIndex(policyName string, policies []PurgePolicy) int {
 	for i, policy := range policies {
@@ -523,18 +526,48 @@ func TestLotMerging(t *testing.T) {
 func TestGetPolicyMap(t *testing.T) {
 	server_utils.ResetTestState()
 	defer server_utils.ResetTestState()
-	viper.SetConfigType("yaml")
-	err := viper.ReadConfig(strings.NewReader(yamlMockup))
-	if err != nil {
-		t.Fatalf("Error reading config: %v", err)
+
+	testCases := []struct {
+		name       string
+		yamlConfig string
+		expectErr  bool
+		expectedPolicies []string
+	}{
+		{
+			name:       "ValidConfig",
+			yamlConfig: yamlMockup,
+			expectErr:  false,
+			expectedPolicies: []string{"different-policy", "another policy"},
+		},
+		{
+			name:       "InvalidConfig",
+			yamlConfig: badYamlMockup,
+			expectErr:  true,
+			expectedPolicies: nil,
+		},
 	}
 
-	policyMap, err := getPolicyMap()
-	require.NoError(t, err)
-	require.Equal(t, 2, len(policyMap))
-	require.Contains(t, policyMap, "different-policy")
-	require.Contains(t, policyMap, "another policy")
-	require.Equal(t, "different-policy", viper.GetString("Lotman.EnabledPolicy"))
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			viper.SetConfigType("yaml")
+			err := viper.ReadConfig(strings.NewReader(tc.yamlConfig))
+			if err != nil {
+				t.Fatalf("Error reading config: %v", err)
+			}
+
+			policyMap, err := getPolicyMap()
+			if tc.expectErr {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				require.Equal(t, len(tc.expectedPolicies), len(policyMap))
+				for _, policy := range tc.expectedPolicies {
+					require.Contains(t, policyMap, policy)
+				}
+				require.Equal(t, "different-policy", viper.GetString("Lotman.EnabledPolicy"))
+			}
+		})
+	}
 }
 
 func TestByteConversions(t *testing.T) {
diff --git a/lotman/resources/malformed-lots-config.yaml b/lotman/resources/malformed-lots-config.yaml
new file mode 100644
index 000000000..b1f2fd91d
--- /dev/null
+++ b/lotman/resources/malformed-lots-config.yaml
@@ -0,0 +1,25 @@
+# ***************************************************************
+#
+#  Copyright (C) 2024, Pelican Project, Morgridge Institute for Research
+#
+#  Licensed under the Apache License, Version 2.0 (the "License"); you
+#  may not use this file except in compliance with the License.  You may
+#  obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+# ***************************************************************
+
+Lotman:
+  EnabledPolicy: "my-bad-policy"
+  PolicyDefinitions:
+    - PolicyName: "my-bad-policy"
+      IShouldCreateAnUnmarshalError: true
+      NoReallyImBad: ["ded", "opp", "exp", "del"]
+      PleaseDontLetMeWork: true