Er/Ho co-doped oxyfluoride germanosilicate glass and glass ceramics are prepared and compared. The results indicate that the glass consists of ${\mathrm{SiO}}_4$ and ${\mathrm{GeO}}_4$ structural units, while the network of the glass ceramics consists of ${\mathrm{SiO}}_4$, ${\mathrm{GeO}}_4$, and ${\mathrm{GeO}}_6$ units together with ${\mathrm{NaYF}}_4$ nanocrystals. The presence of multiple local structures in glass ceramics creates a range of dipole environments, which is beneficial to the broadening of 2.7 μm emission. Two other reasons are attributed to the broadening of 2.7 μm emission in glass ceramics: the energy-level splitting of ${\mathrm{Er}}^{3+}$ and the enhancement of the ${\mathrm{Ho}}^{3+}\text{:}{}^5{\mathrm{I}}_6\to {}^5{\mathrm{I}}_7$ transition in ${\mathrm{NaYF}}_4$ nanocrystals.