diff --git a/plugins/env-files-support/src/main/java/ru/adelf/idea/dotenv/inspections/LowercaseKeyInspection.java b/plugins/env-files-support/src/main/java/ru/adelf/idea/dotenv/inspections/LowercaseKeyInspection.java
new file mode 100644
index 000000000000..02a582a6e1f1
--- /dev/null
+++ b/plugins/env-files-support/src/main/java/ru/adelf/idea/dotenv/inspections/LowercaseKeyInspection.java
@@ -0,0 +1,76 @@
+package ru.adelf.idea.dotenv.inspections;
+
+import com.intellij.codeInspection.*;
+import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.util.IncorrectOperationException;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import ru.adelf.idea.dotenv.DotEnvFactory;
+import ru.adelf.idea.dotenv.psi.*;
+
+public class LowercaseKeyInspection extends LocalInspectionTool {
+    // Change the display name within the plugin.xml
+    // This needs to be here as otherwise the tests will throw errors.
+    @NotNull
+    @Override
+    public String getDisplayName() {
+        return "Key uses lowercase chars";
+    }
+
+    @Nullable
+    @Override
+    public ProblemDescriptor[] checkFile(@NotNull PsiFile file, @NotNull InspectionManager manager, boolean isOnTheFly) {
+        if (!(file instanceof DotEnvFile)) {
+            return null;
+        }
+
+        return analyzeFile(file, manager, isOnTheFly).getResultsArray();
+    }
+
+    @NotNull
+    private ProblemsHolder analyzeFile(@NotNull PsiFile file, @NotNull InspectionManager manager, boolean isOnTheFly) {
+        ProblemsHolder problemsHolder = new ProblemsHolder(manager, file, isOnTheFly);
+
+        PsiTreeUtil.findChildrenOfType(file, DotEnvKey.class).forEach(dotEnvKey -> {
+            if (dotEnvKey.getText().matches(".*[a-z].*")) {
+                problemsHolder.registerProblem(dotEnvKey,
+                        "Key uses lowercase chars. Only keys with uppercase chars are allowed.",
+                        new ForceUppercaseQuickFix()
+                );
+            }
+        });
+
+        return problemsHolder;
+    }
+
+    private static class ForceUppercaseQuickFix implements LocalQuickFix {
+
+        @NotNull
+        @Override
+        public String getName() {
+            return "Change to uppercase";
+        }
+
+        public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+            try {
+                PsiElement psiElement = descriptor.getPsiElement();
+
+                PsiElement newPsiElement = DotEnvFactory.createFromText(project, DotEnvTypes.KEY,
+                        psiElement.getText().toUpperCase() +"=dummy");
+
+                psiElement.replace(newPsiElement);
+            } catch (IncorrectOperationException e) {
+                Logger.getInstance(IncorrectDelimiterInspection.class).error(e);
+            }
+        }
+
+        @NotNull
+        public String getFamilyName() {
+            return getName();
+        }
+    }
+}
diff --git a/plugins/env-files-support/src/main/resources/META-INF/plugin.xml b/plugins/env-files-support/src/main/resources/META-INF/plugin.xml
index e718839d3aa3..167e97f946ac 100644
--- a/plugins/env-files-support/src/main/resources/META-INF/plugin.xml
+++ b/plugins/env-files-support/src/main/resources/META-INF/plugin.xml
@@ -126,6 +126,14 @@
                          level="WARNING"
                          implementationClass="ru.adelf.idea.dotenv.inspections.LeadingCharacterInspection"/>
 
+        <localInspection language="DotEnv"
+                         groupName="DotEnv"
+                         shortName="DotEnvLowercaseKeyInspection"
+                         displayName="Key uses lowercase chars"
+                         enabledByDefault="true"
+                         level="WARNING"
+                         implementationClass="ru.adelf.idea.dotenv.inspections.LowercaseKeyInspection"/>
+
         <lang.syntaxHighlighterFactory language="DotEnv"
                                        implementationClass="ru.adelf.idea.dotenv.DotEnvSyntaxHighlighterFactory"/>
 
diff --git a/plugins/env-files-support/src/main/resources/inspectionDescriptions/DotEnvLowercaseKeyInspection.html b/plugins/env-files-support/src/main/resources/inspectionDescriptions/DotEnvLowercaseKeyInspection.html
new file mode 100644
index 000000000000..0e4b952d5abe
--- /dev/null
+++ b/plugins/env-files-support/src/main/resources/inspectionDescriptions/DotEnvLowercaseKeyInspection.html
@@ -0,0 +1,5 @@
+<html>
+<body>
+Reports keys, which use lowercase chars. Keys should be written in uppercase.
+</body>
+</html>
\ No newline at end of file
diff --git a/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/InspectionsTest.java b/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/InspectionsTest.java
index f13880f2e284..cb7de4d08799 100644
--- a/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/InspectionsTest.java
+++ b/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/InspectionsTest.java
@@ -54,12 +54,18 @@ public class InspectionsTest extends DotEnvLightCodeInsightFixtureTestCase {
         doInspectionTest(new LeadingCharacterInspection(), Collections.singletonList("*LEADING_CHARACTER"));
     }
 
+    @Test
+    public void testLowercaseKeyInspection() {
+        doInspectionTest(new LowercaseKeyInspection(), Collections.singletonList("lower_case_KEY"));
+    }
+
     // Every available quickfix from every inspection is getting applied
     @Test
     public void testQuickFixes() {
         myFixture.enableInspections(new SpaceInsideNonQuotedInspection());
         myFixture.enableInspections(new ExtraBlankLineInspection());
         myFixture.enableInspections(new IncorrectDelimiterInspection());
+        myFixture.enableInspections(new LowercaseKeyInspection());
 
         myFixture.doHighlighting();
         List<IntentionAction> intentionActions = myFixture.getAllQuickFixes();
diff --git a/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/inspections.env b/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/inspections.env
index 73bc8688847e..766f462e1d27 100644
--- a/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/inspections.env
+++ b/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/inspections.env
@@ -10,4 +10,6 @@ SPACE_INSIDE_NON_QUOTED=spaces without quotes
 
 INCORRECT-DELIMITER=test-test
 
-*LEADING_CHARACTER=test
\ No newline at end of file
+*LEADING_CHARACTER=test
+
+lower_case_KEY=test
\ No newline at end of file
diff --git a/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/quickFix.env b/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/quickFix.env
index a25044ee5f6a..f807701b8ad4 100644
--- a/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/quickFix.env
+++ b/plugins/env-files-support/src/test/java/ru/adelf/idea/dotenv/tests/dotenv/fixtures/quickFix.env
@@ -9,4 +9,6 @@ SPACE_INSIDE_NON_QUOTED="spaces without quotes"
 
 INCORRECT_DELIMITER=test-test
 
-*LEADING_CHARACTER=test
\ No newline at end of file
+*LEADING_CHARACTER=test
+
+LOWER_CASE_KEY=test
\ No newline at end of file