• Viscount of Macedo de Cavaleiros • Viscount of Macedo Pinto • Viscount of Macieira • Viscount of Magé • Viscount of Mahem • Viscount of Maiorca • Viscount of Maiors • Viscount of Malanza •
Viscount of Mangualde • Viscount of Manique do Intendente • Viscount of Marco • Viscount of Margaride • Viscount of Mariares • Viscount of Marinha Grande • Viscount of Marinho • Viscount of Marmeleiro • Viscount of Marzovelos • Viscount of Mason de São Domingos • Viscount of Massamá • Viscount of Matalha • Viscount of Mato • Viscount of Mayrink • Viscount of Meireles • Viscount of Melício • Viscount of Melo Barreto • Viscount of Menezes • Viscount of Merceana • Viscount of Mesquitela • Viscount of Messengil • Viscount of Messines • Viscount of Midões (1st) • Viscount of Midões (2nd) • Viscount of Milhundos • Viscount of Mindelo • Viscount of Mira Vouga • Viscount of Miragaia • Viscount of Miranda • Viscount of Miranda do Corvo • Viscount of Mirandela • Viscount of Mogofores • Viscount of Moimenta da Beira •
Viscount of Molelos • Viscount of Monção • Viscount of Monforte • Viscount of Monsanto • Viscount of Monsaraz •
Viscount of Monserrate • Viscount of Montalegre • Viscount of Montalvo • Viscount of Montargil • Viscount of Montariol • Viscount of Monte Belo • Viscount of Monte Redondo • Viscount of Monte São • Viscount of Montedor • Viscount of Montjuïc • Viscount of Morais • Viscount of Morais Cardoso • Viscount of Morais Sarmento • Viscount of Morão • Viscount of Moreira de Rei • Viscount of Moser • Viscount of Mossâmedes • Viscount of Moura • Viscount of Mozelos ==N==