diff --git a/test/test_unit_score_file.py b/test/test_unit_score_file.py
index 9952c0c..673b954 100644
--- a/test/test_unit_score_file.py
+++ b/test/test_unit_score_file.py
@@ -321,3 +321,24 @@ def test_underscores_and_upper_case_in_distro_and_family(runner, yadm):
     assert run.success
     assert run.err == ""
     assert run.out == expected
+
+def test_negative_class_condition(runner, yadm):
+    """Test negative class condition: returns 0 when matching and proper score when not matching."""
+    script = f"""
+        YADM_TEST=1 source {yadm}
+        score=0
+        local_class="testclass"
+        local_classes=("testclass")
+        # Negative condition with matching value should yield delta -1 and zero the score.
+        score_file "filename##!class.testclass" "dest"
+        echo "score: $score"
+        # Negative condition with non-matching value should yield delta 16.
+        score=0
+        score_file "filename##!class.badclass" "dest"
+        echo "score2: $score"
+    """
+    run = runner(command=["bash"], inp=script)
+    assert run.success
+    output = run.out.strip().splitlines()
+    assert output[0] == "score: 0"
+    assert output[1] == "score2: 1016"
diff --git a/yadm b/yadm
index f0c1403..0a529d6 100755
--- a/yadm
+++ b/yadm
@@ -179,6 +179,13 @@ function score_file() {
     local value=${field#*.}
     [ "$field" = "$label" ] && value="" # when .value is omitted
 
+    # Check for negative condition prefix (e.g., "!<label>")
+    local negate=0
+    if [[ "$label" == !* ]]; then
+      negate=1
+      label="${label:1}"
+    fi
+
     shopt -s nocasematch
     local -i delta=-1
     case "$label" in
@@ -186,28 +193,55 @@ function score_file() {
         delta=0
         ;;
       a | arch)
-        [[ "$value" = "$local_arch" ]] && delta=1
+        if [[ "$value" = "$local_arch" ]]; then
+          (( negate )) && delta=-1 || delta=1
+        else
+          (( negate )) && delta=1
+        fi
         ;;
       o | os)
-        [[ "$value" = "$local_system" ]] && delta=2
+        if [[ "$value" = "$local_system" ]]; then
+          (( negate )) && delta=-1 || delta=2
+        else
+          (( negate )) && delta=2
+        fi
         ;;
       d | distro)
-        [[ "${value// /_}" = "${local_distro// /_}" ]] && delta=4
+        if [[ "${value// /_}" = "${local_distro// /_}" ]]; then
+          (( negate )) && delta=-1 || delta=4
+        else
+          (( negate )) && delta=4
+        fi
         ;;
       f | distro_family)
-        [[ "${value// /_}" = "${local_distro_family// /_}" ]] && delta=8
+        if [[ "${value// /_}" = "${local_distro_family// /_}" ]]; then
+          (( negate )) && delta=-1 || delta=8
+        else
+          (( negate )) && delta=8
+        fi
         ;;
       c | class)
-        in_list "$value" "${local_classes[@]}" && delta=16
+        if in_list "$value" "${local_classes[@]}"; then
+          (( negate )) && delta=-1 || delta=16
+        else
+          (( negate )) && delta=16
+        fi
         ;;
       h | hostname)
-        [[ "$value" = "$local_host" ]] && delta=32
+        if [[ "$value" = "$local_host" ]]; then
+          (( negate )) && delta=-1 || delta=32
+        else
+          (( negate )) && delta=32
+        fi
         ;;
       u | user)
-        [[ "$value" = "$local_user" ]] && delta=64
+        if [[ "$value" = "$local_user" ]]; then
+          (( negate )) && delta=-1 || delta=64
+        else
+          (( negate )) && delta=64
+        fi
         ;;
       e | extension)
-        # extension isn't a condition and doesn't affect the score
         continue
         ;;
       t | template | yadm)