diff --git a/colosseum/constants.py b/colosseum/constants.py
index 431c9b6ae..0e7a22571 100644
--- a/colosseum/constants.py
+++ b/colosseum/constants.py
@@ -254,7 +254,29 @@ def value(self, context):
 # 10.8 Leading and half-leading
 ######################################################################
 # line_height
+
 # vertical_align
+BASELINE = 'baseline'
+SUB = 'sub'
+SUPER = 'super'
+TOP = 'top'
+TEXT_TOP = 'text-top'
+MIDDLE = 'middle'
+BOTTOM = 'bottom'
+TEXT_BOTTOM = 'text-bottom'
+
+VERTICAL_ALIGN_CHOICES = Choices(
+    BASELINE,
+    SUB,
+    SUPER,
+    TOP,
+    TEXT_TOP,
+    MIDDLE,
+    BOTTOM,
+    TEXT_BOTTOM,
+    validators=[is_percentage, is_length],
+    explicit_defaulting_constants=[INHERIT],
+)
 
 ######################################################################
 # 11.1.1 Overflow
diff --git a/colosseum/declaration.py b/colosseum/declaration.py
index 4b2515373..53ffd9a24 100644
--- a/colosseum/declaration.py
+++ b/colosseum/declaration.py
@@ -1,30 +1,32 @@
-from . import engine as css_engine
-from . import parser
+from . import engine as css_engine, parser
 from .constants import (  # noqa
     ALIGN_CONTENT_CHOICES, ALIGN_ITEMS_CHOICES, ALIGN_SELF_CHOICES, AUTO,
-    BACKGROUND_COLOR_CHOICES, BORDER_COLLAPSE_CHOICES, BORDER_COLOR_CHOICES,
-    BORDER_SPACING_CHOICES, BORDER_STYLE_CHOICES, BORDER_WIDTH_CHOICES,
-    BOX_OFFSET_CHOICES, CAPTION_SIDE_CHOICES, CLEAR_CHOICES, CLIP_CHOICES,
-    COLOR_CHOICES, DIRECTION_CHOICES, DISPLAY_CHOICES, EMPTY_CELLS_CHOICES,
-    FLEX_BASIS_CHOICES, FLEX_DIRECTION_CHOICES, FLEX_GROW_CHOICES,
-    FLEX_SHRINK_CHOICES, FLEX_START, FLEX_WRAP_CHOICES, FLOAT_CHOICES,
-    GRID_AUTO_CHOICES, GRID_AUTO_FLOW_CHOICES, GRID_GAP_CHOICES,
-    GRID_PLACEMENT_CHOICES, GRID_TEMPLATE_AREA_CHOICES, GRID_TEMPLATE_CHOICES,
-    INITIAL, INLINE, INVERT, JUSTIFY_CONTENT_CHOICES, LETTER_SPACING_CHOICES,
-    LTR, MARGIN_CHOICES, MAX_SIZE_CHOICES, MEDIUM, MIN_SIZE_CHOICES, NORMAL,
-    NOWRAP, ORDER_CHOICES, ORPHANS_CHOICES, OUTLINE_COLOR_CHOICES,
-    OUTLINE_STYLE_CHOICES, OUTLINE_WIDTH_CHOICES, OVERFLOW_CHOICES,
-    PADDING_CHOICES, PAGE_BREAK_AFTER_CHOICES, PAGE_BREAK_BEFORE_CHOICES,
-    PAGE_BREAK_INSIDE_CHOICES, POSITION_CHOICES, QUOTES_CHOICES, ROW,
-    SEPARATE, SHOW, SIZE_CHOICES, STATIC, STRETCH, TABLE_LAYOUT_CHOICES,
+    BACKGROUND_COLOR_CHOICES, BASELINE, BORDER_COLLAPSE_CHOICES,
+    BORDER_COLOR_CHOICES, BORDER_SPACING_CHOICES, BORDER_STYLE_CHOICES,
+    BORDER_WIDTH_CHOICES, BOX_OFFSET_CHOICES, CAPTION_SIDE_CHOICES,
+    CLEAR_CHOICES, CLIP_CHOICES, COLOR_CHOICES, DIRECTION_CHOICES,
+    DISPLAY_CHOICES, EMPTY_CELLS_CHOICES, FLEX_BASIS_CHOICES,
+    FLEX_DIRECTION_CHOICES, FLEX_GROW_CHOICES, FLEX_SHRINK_CHOICES, FLEX_START,
+    FLEX_WRAP_CHOICES, FLOAT_CHOICES, GRID_AUTO_CHOICES,
+    GRID_AUTO_FLOW_CHOICES, GRID_GAP_CHOICES, GRID_PLACEMENT_CHOICES,
+    GRID_TEMPLATE_AREA_CHOICES, GRID_TEMPLATE_CHOICES, INITIAL, INLINE, INVERT,
+    JUSTIFY_CONTENT_CHOICES, LETTER_SPACING_CHOICES, LTR, MARGIN_CHOICES,
+    MAX_SIZE_CHOICES, MEDIUM, MIN_SIZE_CHOICES, NORMAL, NOWRAP, ORDER_CHOICES,
+    ORPHANS_CHOICES, OUTLINE_COLOR_CHOICES, OUTLINE_STYLE_CHOICES,
+    OUTLINE_WIDTH_CHOICES, OVERFLOW_CHOICES, PADDING_CHOICES,
+    PAGE_BREAK_AFTER_CHOICES, PAGE_BREAK_BEFORE_CHOICES,
+    PAGE_BREAK_INSIDE_CHOICES, POSITION_CHOICES, QUOTES_CHOICES, ROW, SEPARATE,
+    SHOW, SIZE_CHOICES, STATIC, STRETCH, TABLE_LAYOUT_CHOICES,
     TEXT_ALIGN_CHOICES, TEXT_DECORATION_CHOICES, TEXT_INDENT_CHOICES,
     TEXT_TRANSFORM_CHOICES, TOP, TRANSPARENT, UNICODE_BIDI_CHOICES,
-    VISIBILITY_CHOICES, VISIBLE, WHITE_SPACE_CHOICES, WIDOWS_CHOICES,
-    WORD_SPACING_CHOICES, Z_INDEX_CHOICES, OtherProperty,
+    VERTICAL_ALIGN_CHOICES, VISIBILITY_CHOICES, VISIBLE, WHITE_SPACE_CHOICES,
+    WIDOWS_CHOICES, WORD_SPACING_CHOICES, Z_INDEX_CHOICES, OtherProperty,
     TextAlignInitialValue, default,
 )
 from .exceptions import ValidationError
-from .wrappers import Border, BorderBottom, BorderLeft, BorderRight, BorderTop, Outline
+from .wrappers import (
+    Border, BorderBottom, BorderLeft, BorderRight, BorderTop, Outline,
+)
 
 _CSS_PROPERTIES = set()
 
@@ -305,7 +307,7 @@ def __init__(self, **style):
 
     # 10.8 Leading and half-leading
     # line_height
-    # vertical_align
+    vertical_align = validated_property('vertical_align', choices=VERTICAL_ALIGN_CHOICES, initial=BASELINE)
 
     # 11. Visual effects #################################################
     # 11.1.1 Overflow