A series of AB(x)-type triarylphosphine oxide monomers, bis-(4-fluorophenyl)-(4-hydroxyphenyl)phosphine oxide (4a), bis-(3,4-difluorophenyl)-(4-hydroxyphenyl)phosphine oxide (4b), and 4-hydroxyphenyl-bis-(3,4,5-trifluorophenyl)phosphine oxide (4c) were prepared, characterized, and polymerized under nucleophilic aromatic substitution conditions [N-methylpyrrolidone (NMP), K2CO3] to provide the corresponding hyperbranched poly(arylene ether phosphine oxide)s with number-average molecular weights ranging from 9200 to 14,600 Da. NMR spectroscopic analysis indicated the presence of highly branched products with an approximate degree of branching of 0.57. The polymers were soluble in a variety of typical organic solvents and displayed excellent thermal stability.