UK parliamentary by-election in Wales
The March 1888 Merthyr Tydfil by-election was a parliamentary by-election held for the House of Commons constituency of Merthyr Tydfil in Wales on 14 March 1888.
Vacancy.
The by-election was caused by the resignation of the sitting Liberal MP, Charles James who was appointed the Steward of the Manor of Northstead. 
Candidates.
The only candidate nominated was industrialist David Alfred Thomas.
Result.
The Liberal Party held the constituency unopposed.
! scope="col" colspan="2" style="width: 130px"|Party
! scope="col" style="width: 17em"|Candidate
! scope="col" style="width: 5em"|Votes
! scope="col" style="width: 3.5em"|%
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! colspan="3" style="text-align:right;" scope=row | Registered electors
References.
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