diff --git a/lib/steep/ast/types/factory.rb b/lib/steep/ast/types/factory.rb
index 330cb09e..ee10e992 100644
--- a/lib/steep/ast/types/factory.rb
+++ b/lib/steep/ast/types/factory.rb
@@ -245,7 +245,7 @@ def function_1(func)
               required_positionals: params.required.map {|type| RBS::Types::Function::Param.new(name: nil, type: type_1(type)) },
               optional_positionals: params.optional.map {|type| RBS::Types::Function::Param.new(name: nil, type: type_1(type)) },
               rest_positionals: params.rest&.yield_self {|type| RBS::Types::Function::Param.new(name: nil, type: type_1(type)) },
-              trailing_positionals: [],
+              trailing_positionals: params.trailing.map {|type| RBS::Types::Function::Param.new(name: nil, type: type_1(type)) },
               required_keywords: params.required_keywords.transform_values {|type| RBS::Types::Function::Param.new(name: nil, type: type_1(type)) },
               optional_keywords: params.optional_keywords.transform_values {|type| RBS::Types::Function::Param.new(name: nil, type: type_1(type)) },
               rest_keywords: params.rest_keywords&.yield_self {|type| RBS::Types::Function::Param.new(name: nil, type: type_1(type)) },
@@ -263,6 +263,7 @@ def params(type)
               required: type.required_positionals.map {|param| type(param.type) },
               optional: type.optional_positionals.map {|param| type(param.type) },
               rest: type.rest_positionals&.yield_self {|param| type(param.type) },
+              trailing: type.trailing_positionals.map {|param| type(param.type) },
               required_keywords: type.required_keywords.transform_values {|param| type(param.type) },
               optional_keywords: type.optional_keywords.transform_values {|param| type(param.type) },
               rest_keywords: type.rest_keywords&.yield_self {|param| type(param.type) }
diff --git a/lib/steep/interface/function.rb b/lib/steep/interface/function.rb
index 8068ad48..1062d82a 100644
--- a/lib/steep/interface/function.rb
+++ b/lib/steep/interface/function.rb
@@ -145,8 +145,11 @@ def size
             1 + (tail&.size || 0)
           end
 
-          def self.build(required:, optional:, rest:)
-            params = rest ? self.rest(rest) : nil
+          def self.build(required:, optional:, rest:, trailing:)
+            # @type var params: Interface::Function::Params::PositionalParams?
+            params = nil
+            params = trailing.reverse_each.inject(params) {|params, type| self.required(type, params) }
+            params = self.rest(rest, params) if rest
             params = optional.reverse_each.inject(params) {|params, type| self.optional(type, params) }
             params = required.reverse_each.inject(params) {|params, type| self.required(type, params) }
 
@@ -769,11 +772,27 @@ def rest
           nil
         end
 
+        def trailing
+          array = [] #: Array[AST::Types::t]
+          trailing = false
+
+          positional_params&.each do |param|
+            case param
+            when PositionalParams::Required
+              array << param.type if trailing
+            when PositionalParams::Optional, PositionalParams::Rest
+              trailing = true
+            end
+          end
+
+          array
+        end
+
         attr_reader :positional_params
         attr_reader :keyword_params
 
-        def self.build(required: [], optional: [], rest: nil, required_keywords: {}, optional_keywords: {}, rest_keywords: nil)
-          positional_params = PositionalParams.build(required: required, optional: optional, rest: rest)
+        def self.build(required: [], optional: [], rest: nil, trailing: [], required_keywords: {}, optional_keywords: {}, rest_keywords: nil)
+          positional_params = PositionalParams.build(required: required, optional: optional, rest: rest, trailing: trailing)
           keyword_params = KeywordParams.new(requireds: required_keywords, optionals: optional_keywords, rest: rest_keywords)
           new(positional_params: positional_params, keyword_params: keyword_params)
         end
diff --git a/sig/steep/interface/function.rbs b/sig/steep/interface/function.rbs
index 85ba9f96..2c9762d5 100644
--- a/sig/steep/interface/function.rbs
+++ b/sig/steep/interface/function.rbs
@@ -76,7 +76,7 @@ module Steep
 
           def size: () -> Integer
 
-          def self.build: (required: Array[AST::Types::t], optional: Array[AST::Types::t], rest: AST::Types::t?) -> PositionalParams?
+          def self.build: (required: Array[AST::Types::t], optional: Array[AST::Types::t], rest: AST::Types::t?, trailing: Array[AST::Types::t]) -> PositionalParams?
 
           extend Utils
 
@@ -145,11 +145,13 @@ module Steep
 
         %a{pure} def rest: () -> AST::Types::t?
 
+        def trailing: () -> Array[AST::Types::t]
+
         attr_reader positional_params: PositionalParams?
 
         attr_reader keyword_params: KeywordParams
 
-        def self.build: (?required: Array[AST::Types::t], ?optional: Array[AST::Types::t], ?rest: AST::Types::t?, ?required_keywords: ::Hash[Symbol, AST::Types::t], ?optional_keywords: ::Hash[Symbol, AST::Types::t], ?rest_keywords: AST::Types::t?) -> Params
+        def self.build: (?required: Array[AST::Types::t], ?optional: Array[AST::Types::t], ?rest: AST::Types::t?, ?trailing: Array[AST::Types::t], ?required_keywords: ::Hash[Symbol, AST::Types::t], ?optional_keywords: ::Hash[Symbol, AST::Types::t], ?rest_keywords: AST::Types::t?) -> Params
 
         def initialize: (positional_params: PositionalParams?, keyword_params: KeywordParams) -> void
 
diff --git a/test/type_check_test.rb b/test/type_check_test.rb
index 3365f4da..dcadd2f9 100644
--- a/test/type_check_test.rb
+++ b/test/type_check_test.rb
@@ -2054,6 +2054,32 @@ def f(x, y, z)
     )
   end
 
+  def test_method_def__trailing
+    run_type_check_test(
+      signatures: {
+        "a.rbs" => <<~RBS
+          class Hello
+            def f: (?untyped a, untyped b) -> void
+          end
+        RBS
+      },
+      code: {
+        "a.rb" => <<~RUBY
+          class Hello
+            def f(a = nil, b)
+              a.to_i + b
+            end
+          end
+        RUBY
+      },
+      expectations: <<~YAML
+        ---
+        - file: a.rb
+          diagnostics: []
+      YAML
+    )
+  end
+
   def test_method_yield__untyped
     run_type_check_test(
       signatures: {