diff --git a/features/apply_with_explicit_parameter_files.feature b/features/apply_with_explicit_parameter_files.feature
new file mode 100644
index 00000000..088d47b1
--- /dev/null
+++ b/features/apply_with_explicit_parameter_files.feature
@@ -0,0 +1,54 @@
+Feature: Apply command with explicit parameter files
+
+  Background:
+    Given a file named "stack_master.yml" with:
+      """
+      stack_defaults:
+        tags:
+          Application: myapp
+        region: us-east-1
+      """
+    And a file named "myapp-web.yml" with:
+      """
+      template: myapp.rb
+      parameter_files:
+      - myapp-web-parameters.yml
+      """
+    And a file named "myapp-web-parameters.yml" with:
+      """
+      KeyName: my-key
+      """
+    And a directory named "templates"
+    And a file named "templates/myapp.rb" with:
+      """
+      SparkleFormation.new(:myapp) do
+        description "Test template"
+
+        parameters.key_name do
+          description 'Key name'
+          type 'String'
+        end
+
+        resources.instance do
+          type 'AWS::EC2::Instance'
+          properties do
+            image_id 'ami-0080e4c5bc078760e'
+            instance_type 't2.micro'
+          end
+        end
+      end
+      """
+
+  Scenario: Run apply with stack-name.yml and explicit parameter files
+    Given I stub the following stack events:
+      | stack_id | event_id | stack_name | logical_resource_id | resource_status | resource_type              | timestamp           |
+      | 1        | 1        | myapp-web  | myapp-web           | CREATE_COMPLETE | AWS::CloudFormation::Stack | 2020-10-29 00:00:00 |
+    When I run `stack_master apply myapp-web.yml --trace`
+    Then the output should match /2020-10-29 00:00:00 (\+|\-)[0-9]{4} myapp-web AWS::CloudFormation::Stack CREATE_COMPLETE/
+    And the output should contain all of these lines:
+      | Stack diff:          |
+      | +    "Instance": {   |
+      | Parameters diff:     |
+      | KeyName: my-key      |
+      | Proposed change set: |
+    And the exit status should be 0
diff --git a/features/apply_with_stack_definition_parameters.feature b/features/apply_with_stack_definition_parameters.feature
new file mode 100644
index 00000000..32d9f9e8
--- /dev/null
+++ b/features/apply_with_stack_definition_parameters.feature
@@ -0,0 +1,46 @@
+Feature: Apply command with stack definition parameters
+
+  Background:
+    Given a file named "stack_master.yml" with:
+      """
+      stacks:
+        us-east-1:
+          myapp_web:
+            template: myapp.rb
+            parameters:
+              KeyName: my-key
+      """
+    And a directory named "templates"
+    And a file named "templates/myapp.rb" with:
+      """
+      SparkleFormation.new(:myapp) do
+        description "Test template"
+
+        parameters.key_name do
+          description 'Key name'
+          type 'String'
+        end
+
+        resources.instance do
+          type 'AWS::EC2::Instance'
+          properties do
+            image_id 'ami-0080e4c5bc078760e'
+            instance_type 't2.micro'
+          end
+        end
+      end
+      """
+
+  Scenario: Run apply with parameters contained in
+    Given I stub the following stack events:
+      | stack_id | event_id | stack_name | logical_resource_id | resource_status | resource_type              | timestamp           |
+      | 1        | 1        | myapp-web  | myapp-web           | CREATE_COMPLETE | AWS::CloudFormation::Stack | 2020-10-29 00:00:00 |
+    When I run `stack_master apply us-east-1 myapp-web --trace`
+    Then the output should match /2020-10-29 00:00:00 (\+|\-)[0-9]{4} myapp-web AWS::CloudFormation::Stack CREATE_COMPLETE/
+    And the output should contain all of these lines:
+      | Stack diff:          |
+      | +    "Instance": {   |
+      | Parameters diff:     |
+      | KeyName: my-key      |
+      | Proposed change set: |
+    And the exit status should be 0
diff --git a/features/apply_with_stack_yml_file.feature b/features/apply_with_stack_yml_file.feature
new file mode 100644
index 00000000..86e80ceb
--- /dev/null
+++ b/features/apply_with_stack_yml_file.feature
@@ -0,0 +1,50 @@
+Feature: Apply command with stack.yml file
+
+  Background:
+    Given a file named "stack_master.yml" with:
+      """
+      stack_defaults:
+        tags:
+          Application: myapp
+        region: us-east-1
+      """
+    And a file named "myapp-web.yml" with:
+      """
+      template: myapp.rb
+      parameters:
+        KeyName: my-key
+      """
+    And a directory named "templates"
+    And a file named "templates/myapp.rb" with:
+      """
+      SparkleFormation.new(:myapp) do
+        description "Test template"
+
+        parameters.key_name do
+          description 'Key name'
+          type 'String'
+        end
+
+        resources.instance do
+          type 'AWS::EC2::Instance'
+          properties do
+            image_id 'ami-0080e4c5bc078760e'
+            instance_type 't2.micro'
+          end
+        end
+      end
+      """
+
+  Scenario: Run apply with stack-name.yml argument
+    Given I stub the following stack events:
+      | stack_id | event_id | stack_name | logical_resource_id | resource_status | resource_type              | timestamp           |
+      | 1        | 1        | myapp-web  | myapp-web           | CREATE_COMPLETE | AWS::CloudFormation::Stack | 2020-10-29 00:00:00 |
+    When I run `stack_master apply myapp-web.yml --trace`
+    Then the output should match /2020-10-29 00:00:00 (\+|\-)[0-9]{4} myapp-web AWS::CloudFormation::Stack CREATE_COMPLETE/
+    And the output should contain all of these lines:
+      | Stack diff:          |
+      | +    "Instance": {   |
+      | Parameters diff:     |
+      | KeyName: my-key      |
+      | Proposed change set: |
+    And the exit status should be 0
diff --git a/lib/stack_master/cli.rb b/lib/stack_master/cli.rb
index f0c5c23b..e36ad066 100644
--- a/lib/stack_master/cli.rb
+++ b/lib/stack_master/cli.rb
@@ -234,27 +234,39 @@ def load_config(file)
     def execute_stacks_command(command, args, options)
       success = true
       config = load_config(options.config)
-      args = [nil, nil] if args.size == 0
-      args.each_slice(2) do |aliased_region, stack_name|
-        region = Utils.underscore_to_hyphen(config.unalias_region(aliased_region))
-        stack_name = Utils.underscore_to_hyphen(stack_name)
-        stack_definitions = config.filter(region, stack_name)
-        if stack_definitions.empty?
-          StackMaster.stdout.puts "Could not find stack definition #{stack_name} in region #{region}"
-          success = false
-        end
-        stack_definitions = stack_definitions.select do |stack_definition|
-          running_in_allowed_account?(stack_definition.allowed_accounts) && StackStatus.new(config, stack_definition).changed?
-        end if options.changed
-        stack_definitions.each do |stack_definition|
-          StackMaster.cloud_formation_driver.set_region(stack_definition.region)
-          StackMaster.stdout.puts "Executing #{command.command_name} on #{stack_definition.stack_name} in #{stack_definition.region}"
-          success = execute_if_allowed_account(stack_definition.allowed_accounts) do
-            command.perform(config, stack_definition, options).success?
+      if args.size == 1 && (args.first.end_with?('.yml') || args.first.end_with?('.yaml'))
+        yaml_file_name = args.first
+        stack_definition = config.build_stack_definition(yaml_file_name)
+        success = run_command_with_stack_definition(command, stack_definition, config, options)
+        @kernel.exit false unless success
+      else
+        args = [nil, nil] if args.size == 0
+        args.each_slice(2) do |aliased_region, stack_name|
+          region = Utils.underscore_to_hyphen(config.unalias_region(aliased_region))
+          stack_name = Utils.underscore_to_hyphen(stack_name)
+          stack_definitions = config.filter(region, stack_name)
+          if stack_definitions.empty?
+            StackMaster.stdout.puts "Could not find stack definition #{stack_name} in region #{region}"
+            success = false
+          end
+          stack_definitions = stack_definitions.select do |stack_definition|
+            running_in_allowed_account?(stack_definition.allowed_accounts) && StackStatus.new(config, stack_definition).changed?
+          end if options.changed
+          stack_definitions.each do |stack_definition|
+            success = run_command_with_stack_definition(command, stack_definition, config, options)
           end
         end
+        @kernel.exit false unless success
+      end
+    end
+
+    def run_command_with_stack_definition(command, stack_definition, config, options)
+      StackMaster.cloud_formation_driver.set_region(stack_definition.region)
+
+      StackMaster.stdout.puts "Executing #{command.command_name} on #{stack_definition.stack_name} in #{stack_definition.region}"
+      execute_if_allowed_account(stack_definition.allowed_accounts) do
+        command.perform(config, stack_definition, options).success?
       end
-      @kernel.exit false unless success
     end
 
     def execute_if_allowed_account(allowed_accounts, &block)
diff --git a/lib/stack_master/commands/tidy.rb b/lib/stack_master/commands/tidy.rb
index d7fc63b1..24b440e8 100644
--- a/lib/stack_master/commands/tidy.rb
+++ b/lib/stack_master/commands/tidy.rb
@@ -12,7 +12,7 @@ def perform
         parameter_files = Set.new(find_parameter_files())
 
         status = @config.stacks.each do |stack_definition|
-          parameter_files.subtract(stack_definition.parameter_files)
+          parameter_files.subtract(stack_definition.parameter_files_from_globs)
           template = File.absolute_path(stack_definition.template_file_path)
 
           if template
diff --git a/lib/stack_master/config.rb b/lib/stack_master/config.rb
index f85e797f..6c54780a 100644
--- a/lib/stack_master/config.rb
+++ b/lib/stack_master/config.rb
@@ -67,7 +67,15 @@ def unalias_region(region)
       @region_aliases.fetch(region) { region }
     end
 
+    def build_stack_definition(yaml_file)
+      stack_name = yaml_file.sub('.yml', '').sub('.yaml', '')
+      attributes = YAML.load(File.read(yaml_file))
+      stack_attributes = merge_stack_attributes(nil, stack_name, attributes)
+      StackDefinition.new(stack_attributes)
+    end
+
     private
+
     def load_template_compilers(config)
       @template_compilers = {}
       populate_template_compilers(config.fetch('template_compilers', {}))
@@ -94,7 +102,7 @@ def default_template_compilers
     end
 
     def load_config
-      unaliased_stacks = resolve_region_aliases(@config.fetch('stacks'))
+      unaliased_stacks = resolve_region_aliases(@config.fetch('stacks', {}))
       load_stacks(unaliased_stacks)
     end
 
@@ -110,18 +118,25 @@ def load_stacks(stacks)
         region = Utils.underscore_to_hyphen(region)
         stacks_for_region.each do |stack_name, attributes|
           stack_name = Utils.underscore_to_hyphen(stack_name)
-          stack_attributes = build_stack_defaults(region).deeper_merge!(attributes).merge(
-            'region' => region,
-            'stack_name' => stack_name,
-            'base_dir' => @base_dir,
-            'template_dir' => @template_dir,
-            'additional_parameter_lookup_dirs' => @region_to_aliases[region])
-          stack_attributes['allowed_accounts'] = attributes['allowed_accounts'] if attributes['allowed_accounts']
+          stack_attributes = merge_stack_attributes(region, stack_name, attributes)
           @stacks << StackDefinition.new(stack_attributes)
         end
       end
     end
 
+    def merge_stack_attributes(region, stack_name, attributes)
+      stack_attributes = build_stack_defaults(region)
+        .deeper_merge!(attributes)
+        .merge(
+        'region' => region,
+        'stack_name' => stack_name,
+        'base_dir' => @base_dir,
+        'template_dir' => @template_dir,
+        'additional_parameter_lookup_dirs' => @region_to_aliases[region])
+      stack_attributes['allowed_accounts'] = attributes['allowed_accounts'] if attributes['allowed_accounts']
+      stack_attributes
+    end
+
     def build_stack_defaults(region)
       region_defaults = @region_defaults.fetch(region, {}).deep_dup
       @stack_defaults.deep_dup.deeper_merge(region_defaults)
diff --git a/lib/stack_master/parameter_loader.rb b/lib/stack_master/parameter_loader.rb
index 452be95a..64dacfce 100644
--- a/lib/stack_master/parameter_loader.rb
+++ b/lib/stack_master/parameter_loader.rb
@@ -5,10 +5,10 @@ class ParameterLoader
 
     COMPILE_TIME_PARAMETERS_KEY = 'compile_time_parameters'
 
-    def self.load(parameter_files)
+    def self.load(parameter_files: [], parameters: {})
       StackMaster.debug 'Searching for parameter files...'
-      parameter_files.reduce({template_parameters: {}, compile_time_parameters: {}}) do |hash, file_name|
-        parameters = load_parameters(file_name)
+      all_parameters = parameter_files.map { |file_name| load_parameters(file_name) } + [parameters]
+      all_parameters.reduce({template_parameters: {}, compile_time_parameters: {}}) do |hash, parameters|
         template_parameters = create_template_parameters(parameters)
         compile_time_parameters = create_compile_time_parameters(parameters)
 
@@ -16,7 +16,6 @@ def self.load(parameter_files)
         merge_and_camelize(hash[:compile_time_parameters], compile_time_parameters)
         hash
       end
-
     end
 
     private
diff --git a/lib/stack_master/stack.rb b/lib/stack_master/stack.rb
index ebb6a283..8c07ef2c 100644
--- a/lib/stack_master/stack.rb
+++ b/lib/stack_master/stack.rb
@@ -56,7 +56,7 @@ def self.find(region, stack_name)
     end
 
     def self.generate(stack_definition, config)
-      parameter_hash = ParameterLoader.load(stack_definition.parameter_files)
+      parameter_hash = ParameterLoader.load(parameter_files: stack_definition.all_parameter_files, parameters: stack_definition.parameters)
       template_parameters = ParameterResolver.resolve(config, stack_definition, parameter_hash[:template_parameters])
       compile_time_parameters = ParameterResolver.resolve(config, stack_definition, parameter_hash[:compile_time_parameters])
       template_body = TemplateCompiler.compile(config, stack_definition.compiler, stack_definition.template_dir, stack_definition.template, compile_time_parameters, stack_definition.compiler_options)
diff --git a/lib/stack_master/stack_definition.rb b/lib/stack_master/stack_definition.rb
index 587afb77..56bc0295 100644
--- a/lib/stack_master/stack_definition.rb
+++ b/lib/stack_master/stack_definition.rb
@@ -16,7 +16,9 @@ class StackDefinition
                   :additional_parameter_lookup_dirs,
                   :s3,
                   :files,
-                  :compiler_options
+                  :compiler_options,
+                  :parameters,
+                  :parameter_files
 
     attr_reader :compiler
 
@@ -34,6 +36,8 @@ def initialize(attributes = {})
       @additional_parameter_lookup_dirs ||= []
       @template_dir ||= File.join(@base_dir, 'templates')
       @allowed_accounts = Array(@allowed_accounts)
+      @parameters ||= {}
+      @parameter_files ||= []
     end
 
     def ==(other)
@@ -85,7 +89,11 @@ def s3_template_file_name
       Utils.change_extension(template, 'json')
     end
 
-    def parameter_files
+    def all_parameter_files
+      parameter_files_from_globs + parameter_files
+    end
+
+    def parameter_files_from_globs
       parameter_file_globs.map(&Dir.method(:glob)).flatten
     end
 
diff --git a/spec/stack_master/parameter_loader_spec.rb b/spec/stack_master/parameter_loader_spec.rb
index 9d6015b1..65739e9e 100644
--- a/spec/stack_master/parameter_loader_spec.rb
+++ b/spec/stack_master/parameter_loader_spec.rb
@@ -2,7 +2,7 @@
   let(:stack_file_name) { '/base_dir/parameters/stack_name.yml' }
   let(:region_file_name) { '/base_dir/parameters/us-east-1/stack_name.yml' }
 
-  subject(:parameters) { StackMaster::ParameterLoader.load([stack_file_name, region_file_name]) }
+  subject(:parameters) { StackMaster::ParameterLoader.load(parameter_files: [stack_file_name, region_file_name]) }
 
   before do
     file_mock(stack_file_name, **stack_file_returns)
@@ -60,7 +60,7 @@
     let(:region_yaml_file_returns) { {exists: true, read: "Param1: value1\nParam2: valueX"} }
     let(:region_yaml_file_name) { "/base_dir/parameters/us-east-1/stack_name.yaml" }
 
-    subject(:parameters) { StackMaster::ParameterLoader.load([stack_file_name, region_yaml_file_name, region_file_name]) }
+    subject(:parameters) { StackMaster::ParameterLoader.load(parameter_files: [stack_file_name, region_yaml_file_name, region_file_name]) }
 
     before do
       file_mock(region_yaml_file_name, **region_yaml_file_returns)
diff --git a/spec/stack_master/stack_definition_spec.rb b/spec/stack_master/stack_definition_spec.rb
index b9deb16e..a01886b0 100644
--- a/spec/stack_master/stack_definition_spec.rb
+++ b/spec/stack_master/stack_definition_spec.rb
@@ -35,7 +35,7 @@
   end
 
   it 'has default and region specific parameter file locations' do
-    expect(stack_definition.parameter_files).to eq([
+    expect(stack_definition.all_parameter_files).to eq([
       "/base_dir/parameters/#{stack_name}.yaml",
       "/base_dir/parameters/#{stack_name}.yml",
       "/base_dir/parameters/#{region}/#{stack_name}.yaml",
@@ -75,7 +75,7 @@
     end
 
     it 'includes a parameter lookup dir for it' do
-      expect(stack_definition.parameter_files).to eq([
+      expect(stack_definition.all_parameter_files).to eq([
         "/base_dir/parameters/#{stack_name}.yaml",
         "/base_dir/parameters/#{stack_name}.yml",
         "/base_dir/parameters/#{region}/#{stack_name}.yaml",
diff --git a/spec/stack_master/template_compiler_spec.rb b/spec/stack_master/template_compiler_spec.rb
index 403de7f7..5b018c9b 100644
--- a/spec/stack_master/template_compiler_spec.rb
+++ b/spec/stack_master/template_compiler_spec.rb
@@ -13,7 +13,7 @@ def self.compile(template_dir, template, compile_time_parameters, compile_option
     context 'when a template compiler is explicitly specified' do
       it 'uses it' do
         expect(StackMaster::TemplateCompilers::SparkleFormation).to receive(:compile).with('/base_dir/templates', 'template', compile_time_parameters, anything)
-        StackMaster::TemplateCompiler.compile(config, :sparkle_formation, '/base_dir/templates', 'template', compile_time_parameters, compile_time_parameters)
+        StackMaster::TemplateCompiler.compile(config, :sparkle_formation, '/base_dir/templates', 'template', compile_time_parameters, {})
       end
     end