Two-photon polymerization (TPP) is enabling fabrication of structures with a combination of small scale resolution and geometric freedom beyond previous capabilities. [1] As such, it has become a popular fabrication technique to study physical systems and phenomena across many disciplines where miniaturization and effects on the nano and microscales are relevant, including optics, [2][3][4][5][6][7] biology, [8][9][10] bioengineering, [11][12][13] robotics, [14][15][16] and solid mechanics. [17][18][19][20] Yet, fabrication with TPP in the most commonly used configuration-where the objective lens of the microscope is in direct contact with a liquid resist-still poses critical design constraints. For example, studies of microlattices have noted that these structure are too delicate to be fabricated when their struts are more than 17.5 times longer than Additive manufacturing with two-photon polymerization (TPP) has opened new opportunities for the rapid fabrication of 3D structures with sub-micrometer resolution, but there are still many fabrication constraints associated with this technique. This study details a postprocessing method utilizing oxygen-plasma etching to increase the capabilities of TPP. Underutilized precision in the typical fabrication process allows this subtractive technique to dramatically reduce the minimum achievable feature size. Moreover, since the postprocessing occurs in a dry environment, high aspect ratio features that cannot survive the typical fabrication route can also be achieved. Finally, it is shown that the technique also provides a pathway to realize structures that otherwise are too delicate to be fabricated with TPP, as it enables to introduce temporary support material that can be removed with the plasma. As such, the proposed approach grants access to a massively expanded design domain, providing new capabilities that are long sought in many fields, including optics, biology, robotics, and solid mechanics. Direct Laser Writing their diameter. [21] Additionally, it has been observed that the resolution of the technique sets a lower bound for the strut diameters to be around 1 µm. [19] To overcome these limitations, a number of variations of TPP have been explored. [22][23][24][25][26][27][28] Out of these, the stimulated emission depletion (STED) approach is particularly promising and has demonstrated the smallest feature sizes, allowing for the fabrication of freestanding 3D structures with strut cross-sectional dimensions as small as 120 × 170 nm [29] with resolutions of 175 and 375 nm in the sense of Abbe and Sparrow, respectively. [30] However, the STED approach requires complexity in setup that is currently out of reach to most researchers and has only been demonstrated using the conventional oil-immersion configuration, which is decreasing in popularity and limits structures to be less than 100 µm in height. Alternative approaches to enhancing the capabilities of TPP through subtractive methods have also recently been proposed. In particular, new photoresist chemistries...