Global Developmental Delay (GDD) is a subset of developmental disabilities with early onset and relates to children who experience significant delay in two or more developmental domains (e.g. gross/fine motor, speech/language, cognition, social/emotional) compared to their chronological peers.

The term GDD is often reserved for younger children (under 5 years of age).  The prevalence of GDD is uncertain and disputed but is estimated to be between 1 and 5% of children.  The causes of GDD are varied but often relate to chromosome and genetic disorders such as Down Syndrome or fragile x syndrome, or may be due to abnormalities in spinal cord or brain development such as spina bifida or cerebral palsy.  In some cases the exact cause of GDD remains unclear.

Children with GDD may miss developmental milestones in two or more of the following areas:

1. motor skills: children may be late in developing gross motor skills (such as sitting up) or fine motor skills (such as picking up smaller objects)
2. speech and language skills: children may be delayed in understanding language and in producing language or gesture (such as babbling, imitation)
3. cognitive skills: children may be slower to develop their skills in reasoning, memory, learning new things
4. social and emotional skills: children may be delayed in their ability to interact with others

It is recognised that early identification is centrally important to enhancing the future development of children with GDD.  Increasingly children with GDD are identified at, soon after or even before birth, so that intervention support in the form of physiotherapy, occupational therapy or speech and language therapy can be put in place from an early age.