diff --git a/test/towerops/snmp/mib_parser_test.exs b/test/towerops/snmp/mib_parser_test.exs
new file mode 100644
index 00000000..fbd29ed4
--- /dev/null
+++ b/test/towerops/snmp/mib_parser_test.exs
@@ -0,0 +1,343 @@
+defmodule Towerops.Snmp.MibParserTest do
+  use ExUnit.Case, async: true
+
+  alias Towerops.Snmp.MibParser
+
+  describe "parse_mib_content/1" do
+    test "parses simple OBJECT-TYPE definitions" do
+      content = """
+      sysDescr OBJECT-TYPE
+        ::= { system 1 }
+
+      sysName OBJECT-TYPE
+        ::= { system 5 }
+      """
+
+      oids = MibParser.parse_mib_content(content)
+
+      assert is_map(oids)
+      # These won't resolve without parent "system" being defined as a root
+      # but they should be extracted as assignments
+    end
+
+    test "parses OBJECT IDENTIFIER definitions" do
+      content = """
+      enterprises OBJECT IDENTIFIER ::= { private 1 }
+      mikrotik OBJECT IDENTIFIER ::= { enterprises 14988 }
+      """
+
+      oids = MibParser.parse_mib_content(content)
+
+      assert is_map(oids)
+      # enterprises should resolve to 1.3.6.1.4.1
+      assert Map.get(oids, "enterprises") == "1.3.6.1.4.1"
+    end
+
+    test "removes comments before parsing" do
+      content = """
+      -- This is a comment
+      sysDescr OBJECT-TYPE  -- inline comment
+        ::= { system 1 }
+      -- Another comment
+      """
+
+      oids = MibParser.parse_mib_content(content)
+
+      # Should parse without errors
+      assert is_map(oids)
+    end
+
+    test "resolves OIDs with known roots" do
+      content = """
+      parent OBJECT IDENTIFIER ::= { enterprises 999 }
+      myObject OBJECT-TYPE ::= { parent 1 }
+      """
+
+      oids = MibParser.parse_mib_content(content)
+
+      assert Map.get(oids, "parent") == "1.3.6.1.4.1.999"
+      assert Map.get(oids, "myObject") == "1.3.6.1.4.1.999.1"
+    end
+
+    test "resolves nested OID assignments" do
+      content = """
+      parent OBJECT IDENTIFIER ::= { enterprises 100 }
+      child OBJECT-TYPE ::= { parent 5 }
+      grandchild OBJECT-TYPE ::= { child 3 }
+      """
+
+      oids = MibParser.parse_mib_content(content)
+
+      assert Map.get(oids, "parent") == "1.3.6.1.4.1.100"
+      assert Map.get(oids, "child") == "1.3.6.1.4.1.100.5"
+      assert Map.get(oids, "grandchild") == "1.3.6.1.4.1.100.5.3"
+    end
+
+    test "includes well-known root OIDs" do
+      oids = MibParser.parse_mib_content("")
+
+      assert Map.get(oids, "iso") == "1"
+      assert Map.get(oids, "internet") == "1.3.6.1"
+      assert Map.get(oids, "mib-2") == "1.3.6.1.2.1"
+      assert Map.get(oids, "enterprises") == "1.3.6.1.4.1"
+    end
+
+    test "handles empty content" do
+      oids = MibParser.parse_mib_content("")
+
+      assert is_map(oids)
+      # Should have root OIDs
+      assert map_size(oids) > 0
+    end
+
+    test "handles multiline definitions" do
+      content = """
+      sysDescr OBJECT-TYPE
+        SYNTAX      DisplayString (SIZE (0..255))
+        MAX-ACCESS  read-only
+        STATUS      current
+        DESCRIPTION
+          "A textual description of the entity."
+        ::= { system 1 }
+      """
+
+      oids = MibParser.parse_mib_content(content)
+
+      assert is_map(oids)
+    end
+
+    test "extracts multiple objects from real-world MIB structure" do
+      content = """
+      mycompany OBJECT IDENTIFIER ::= { enterprises 12345 }
+      system OBJECT IDENTIFIER ::= { mycompany 1 }
+
+      sysDescr OBJECT-TYPE
+        ::= { system 1 }
+
+      sysObjectID OBJECT-TYPE
+        ::= { system 2 }
+
+      sysUpTime OBJECT-TYPE
+        ::= { system 3 }
+      """
+
+      oids = MibParser.parse_mib_content(content)
+
+      assert Map.get(oids, "mycompany") == "1.3.6.1.4.1.12345"
+      assert Map.get(oids, "system") == "1.3.6.1.4.1.12345.1"
+      assert Map.get(oids, "sysDescr") == "1.3.6.1.4.1.12345.1.1"
+      assert Map.get(oids, "sysObjectID") == "1.3.6.1.4.1.12345.1.2"
+      assert Map.get(oids, "sysUpTime") == "1.3.6.1.4.1.12345.1.3"
+    end
+  end
+
+  describe "parse_mib_file/1" do
+    test "returns error for non-existent file" do
+      assert {:error, :enoent} = MibParser.parse_mib_file("/nonexistent/file")
+    end
+
+    test "returns error with descriptive message for missing file" do
+      result = MibParser.parse_mib_file("/tmp/does_not_exist_#{:rand.uniform(1000)}")
+
+      assert match?({:error, _}, result)
+    end
+
+    @tag :tmp_dir
+    test "parses valid MIB file", %{tmp_dir: tmp_dir} do
+      mib_file = Path.join(tmp_dir, "TEST-MIB")
+
+      File.write!(mib_file, """
+      TEST-MIB DEFINITIONS ::= BEGIN
+
+      testObject OBJECT-TYPE ::= { enterprises 9999 }
+      testChild OBJECT-TYPE ::= { testObject 1 }
+
+      END
+      """)
+
+      assert {:ok, oids} = MibParser.parse_mib_file(mib_file)
+      assert is_map(oids)
+      assert Map.get(oids, "testObject") == "1.3.6.1.4.1.9999"
+      assert Map.get(oids, "testChild") == "1.3.6.1.4.1.9999.1"
+    end
+
+    @tag :tmp_dir
+    test "handles MIB file with complex structure", %{tmp_dir: tmp_dir} do
+      mib_file = Path.join(tmp_dir, "COMPLEX-MIB")
+
+      File.write!(mib_file, """
+      COMPLEX-MIB DEFINITIONS ::= BEGIN
+
+      -- Root object
+      myCompany OBJECT IDENTIFIER ::= { enterprises 12345 }
+
+      -- Product line
+      products OBJECT IDENTIFIER ::= { myCompany 1 }
+      services OBJECT IDENTIFIER ::= { myCompany 2 }
+
+      -- Specific products
+      productA OBJECT IDENTIFIER ::= { products 1 }
+      productB OBJECT IDENTIFIER ::= { products 2 }
+
+      -- Product A metrics
+      productAUptime OBJECT-TYPE ::= { productA 1 }
+      productAStatus OBJECT-TYPE ::= { productA 2 }
+
+      END
+      """)
+
+      assert {:ok, oids} = MibParser.parse_mib_file(mib_file)
+
+      assert Map.get(oids, "myCompany") == "1.3.6.1.4.1.12345"
+      assert Map.get(oids, "products") == "1.3.6.1.4.1.12345.1"
+      assert Map.get(oids, "productA") == "1.3.6.1.4.1.12345.1.1"
+      assert Map.get(oids, "productAUptime") == "1.3.6.1.4.1.12345.1.1.1"
+    end
+  end
+
+  describe "validate_oid/3" do
+    @tag :tmp_dir
+    test "returns :ok when OID matches", %{tmp_dir: tmp_dir} do
+      mib_file = Path.join(tmp_dir, "VALID-MIB")
+
+      File.write!(mib_file, """
+      testObj OBJECT-TYPE ::= { enterprises 1234 }
+      """)
+
+      assert :ok = MibParser.validate_oid(mib_file, "testObj", "1.3.6.1.4.1.1234")
+    end
+
+    @tag :tmp_dir
+    test "returns error when OID does not match", %{tmp_dir: tmp_dir} do
+      mib_file = Path.join(tmp_dir, "MISMATCH-MIB")
+
+      File.write!(mib_file, """
+      testObj OBJECT-TYPE ::= { enterprises 1234 }
+      """)
+
+      assert {:error, msg} = MibParser.validate_oid(mib_file, "testObj", "1.3.6.1.4.1.9999")
+      assert msg =~ "OID mismatch"
+      assert msg =~ "expected 1.3.6.1.4.1.9999"
+      assert msg =~ "got 1.3.6.1.4.1.1234"
+    end
+
+    @tag :tmp_dir
+    test "returns error when object not found in MIB", %{tmp_dir: tmp_dir} do
+      mib_file = Path.join(tmp_dir, "MISSING-MIB")
+
+      File.write!(mib_file, """
+      existingObj OBJECT-TYPE ::= { enterprises 1234 }
+      """)
+
+      assert {:error, msg} = MibParser.validate_oid(mib_file, "missingObj", "1.3.6.1.4.1.9999")
+      assert msg =~ "not found in MIB"
+    end
+
+    test "returns error when MIB file does not exist" do
+      assert {:error, msg} = MibParser.validate_oid("/nonexistent", "obj", "1.2.3")
+      assert msg =~ "Failed to parse MIB"
+    end
+  end
+
+  describe "list_mib_files/0" do
+    test "returns a list" do
+      files = MibParser.list_mib_files()
+      assert is_list(files)
+    end
+
+    test "returns absolute paths" do
+      files = MibParser.list_mib_files()
+
+      if length(files) > 0 do
+        Enum.each(files, fn path ->
+          assert String.starts_with?(path, "/")
+        end)
+      end
+    end
+
+    test "only returns files ending with MIB" do
+      files = MibParser.list_mib_files()
+
+      Enum.each(files, fn path ->
+        assert String.ends_with?(Path.basename(path), "MIB")
+      end)
+    end
+
+    test "searches in subdirectories" do
+      files = MibParser.list_mib_files()
+
+      # Should find MIBs in different subdirectories
+      if length(files) > 0 do
+        # At least some files should be in subdirectories
+        subdirs =
+          files
+          |> Enum.map(&Path.dirname/1)
+          |> Enum.uniq()
+
+        # Should have multiple subdirectories
+        assert length(subdirs) >= 1
+      end
+    end
+  end
+
+  describe "edge cases" do
+    test "handles whitespace variations in assignments" do
+      content = """
+      obj1 OBJECT-TYPE::={parent 1}
+      obj2 OBJECT-TYPE ::= {parent 2}
+      obj3 OBJECT-TYPE ::=  {  parent  3  }
+      """
+
+      oids = MibParser.parse_mib_content(content)
+      assert is_map(oids)
+    end
+
+    test "handles definitions with hyphens in names" do
+      content = """
+      my-object OBJECT-TYPE ::= { mib-2 999 }
+      """
+
+      # Hyphens in identifiers are actually invalid in the regex
+      # This documents current behavior
+      oids = MibParser.parse_mib_content(content)
+      # Won't match due to \\w+ in regex
+      refute Map.has_key?(oids, "my-object")
+    end
+
+    test "handles numeric parent references" do
+      content = """
+      obj OBJECT-TYPE ::= { 1 3 6 1 2 1 999 }
+      """
+
+      # This format isn't supported by the parser
+      # Documents current limitation
+      oids = MibParser.parse_mib_content(content)
+      refute Map.has_key?(oids, "obj")
+    end
+
+    test "preserves root OIDs when parsing empty MIB" do
+      oids = MibParser.parse_mib_content("")
+
+      # All well-known roots should be present
+      expected_roots = [
+        "iso",
+        "org",
+        "dod",
+        "internet",
+        "directory",
+        "mgmt",
+        "mib-2",
+        "experimental",
+        "private",
+        "enterprises",
+        "security",
+        "snmpV2",
+        "snmpModules"
+      ]
+
+      Enum.each(expected_roots, fn root ->
+        assert Map.has_key?(oids, root), "Missing root OID: #{root}"
+      end)
+    end
+  end
+end